Lowly lactone-modified reactive monomer composition, acrylic polyol resins produced with the same, curable resin compositions and coating compositions

ABSTRACT

This invention provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones in which a proportion of monomers having two or more continuous chains of lactone is less than 50% (area % by GPC). This invention also provides methods for synthesizing such a composition. This invention also provides an acrylic polyol resin comprising the hydroxyalkyl(meth)acrylate composition, a carboxylic group-containing acrylate composition modified by a small amount of lactones, and a polyester unsaturated monomer modified by a small amount of lactones. Uses of these materials in curable resins, coating compositions, and finishing agents are also provided.

TECHNICAL FIELD

The present invention I relates to a hydroxyalkyl(meth)acrylatecomposition modified by a small amount of lactones in which there isdecreased the amount of adducts containing two or more continuouslactone chains, a method for the preparation thereof, and an acrylicpolyol resin which can be employed as an industrial finishing agenthaving a high quality and which is variously well-balanced, for example,coatings and a pressure-sensitive adhesive, an ultraviolet ray- orelectron beam-curable coating agent, and a reactive modifier.

Further, the present invention II relates to a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones.

Still further, the present invention III relates to a curable resincomposition comprising an acrylic polyol resin containing thehydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as a polymerizable component and a melamine resin, by whichthere can be prepared a coating having an improved acid resistance andbeing well-balanced in abrasion resistance and an acid resistance.

Furthermore, the present invention IV relates to a melamine-curable typewater-based coating composition comprising the acrylic polyol resincontaining the hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones and an amino-plasto resin, and which isappropriate as a water-based coating for cars, home electric appliances,and cans for beverages and foods, particularly, which is appropriate asa clear coating for finishing an outer surface of cans.

In addition, the present invention V relates to a curable resincomposition containing an acrylic polyol resin obtained by employing thehydroxyalkyl(meth)acrylate composition modified by a small amount oflactones in which there are decreased adducts containing two or morecontinuous lactone chains and a polyisocyanate compound as essentialcomponents, by which there can be prepared a coating having a long potlife and an excellent abrasion resistance and water resistance.

Also, the present invention VI relates to a coating containing a curableresin composition and crosslinked particles obtained from the curableresin composition or urethane-urea/ethylenic resin-composite typecrosslinked particles as essential coating layer-formable components.The curable resin composition essentially contains ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones and a polyisocyanate compound as essential components. Thehydroxyalkyl(meth)acrylate composition is a vinyl-based copolymer havingcarboxylic group and a crosslinkable functional group. The vinyl-basedcopolymer is obtained by allowing to react thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones with a carboxylic group-contained vinyl-based monomer and othervinyl-based monomers.

The vinyl-based copolymer is the acrylic polyol resin (A) in the curableresin composition of the present invention V.

And also, the present invention VII relates to a thermosetting resincomposition comprising an acrylic polyol resin containing thehydroxyalkyl(meth)acrylate composition modified by a small amount oflactones and an alkoxysilyl group-contained acrylic copolymer, andrelates to a top-coat clear coating primarily containing thethermosetting resin composition, and which is employed as an outercoating for buildings, a variety of coatings for cars, industrialmachines, a steel-made furniture, home electric appliances, andplastics, in which durability is particularly required.

Besides, the present invention VIII relates to a carboxylicgroup-contained acrylate modified by a small amount of lactones which isuseful as a raw material for resins.

Also, the present invention IX relates to a curable resin composition, aclear coating composition, and a method for coating, and the curableresin composition is employed as a finishing coating for cars and coilcoating, etc., which is composed of an acrylic polycarboxylic acid resincontaining a carboxylic group-contained acrylate monomer modified by asmall amount of lactones and a polyepoxide.

And also, the present invention X relates to a polyester unsaturatedmonomer composition modified by a small amount of lactones, a method forthe preparation thereof, and an acrylic resin prepared therefrom whichdoes not show tackiness.

By allowing to react these monomer compositions with other ethylenicunsaturated monomer and formulating with a variety of crosslinkingagents and other components which are usually employed, there can beprepared an industrial finishing agent which is variously well-balanced,for example, a coating, an pressure-sensitive adhesive, an ultravioletray- or electron beam-curable coating agent, a curable oligomer and apolymer which can be employed as a reactive modifier, etc.

BACKGROUND ART I and II

In recent years, there has been raised an importance of an acrylic-basedcoating in a coating field.

It is a reason that it has an excellent characteristic inweatherability, chemical resistance, and staining resistance, etc.compared to other alkyd resins, polyester resins, and epoxy resins.

For that reason, an acrylic-based coating has been employed in manyfields such as cars, home electric appliances, metals, and constructionmaterials.

Of acrylic resins, an acrylic polyol in which a monomer having hydroxylgroup is copolymerized is applied as an ordinary temperature-curablecoating or a baking-curable coating in which there is formulated acrosslinking agent which is capable of reacting with hydroxyl group, forexample, a polyisocyanate and a melamine resin, etc. The monomer havinghydroxyl group is indispensable in order to give adhesion to a coatinglayer and a gasoline resistance.

As the monomer having hydroxyl group, there have been conventionallyemployed a hydroxyethyl(meth)acrylate and hydroxypropyl(meth)acrylate,etc. Herein, the (meth)acrylate means an acrylate and a methacrylate.

However, hydroxyl groups in an acrylic polyol prepared bycopolymerization of the monomers do not show a sufficient reactivitywith the crosslinking agent because it is situated in a position whichis exceedingly near by a main chain of a rigid acrylic resin skeleton.

For the purpose of improvement thereof, although 4-hydroxybutylacrylateis proposed, it is difficult to say that reactivity thereof issufficient.

In order to solve problems, there has been employed a means forsynthesizing a lactone-modified acrylic polyol in which ε-caprolactoneis allowed to addition-react to a hydroxyalkylacrylate or ahydroxalkylmethacrylate, followed by copolymerizing with other monomers.

By the means, although reactivity with the crosslinking agent andductility can be solved, a distribution of lactone continuous chains isbroad in a conventional lactone-modified (meth)acrylate, and the number(n) of the lactone continuous chains becomes large and, whereby,although curing reactivity and ductility are improved, there isoccasionally caused a problem that there lower hardness and acidresistance, etc.

For example, in the case that there is employed a hydroxyalkylacrylateor a hydroxyalkylmethacrylate having the large number of the lactonecontinuous chain in which ε-caprolactone is added as a raw material in atop-coat coating for cars, since a hydroxyl value per the unit weight ofa product becomes lower, a large amount of the acrylate or methacrylatemust be employed in order to adjust the hydroxyl value, whereby, thereare occasionally deteriorated other requiring items such as a glossinessand an acid resistance other than the abrasion resistance.

Further, although it is occasionally controlled using ahydroxyethylacrylate or hydroxyethylmethacrylate in order to adjust thehydroxyl value without feeding a large amount of a lactone-modifiedhydroxyalkylacrylate or hydroxyalkyl methacrylate, in the case, therebecomes smaller a proportion of a hydroxyalkyl(meth)acrylate containing1 mol of the lactone single chain in which the number of “n” is 1, inwhich ductility and hardness are well-balanced.

III

In a coating layer for cars, it is looked upon that there areproblematic a durability of the coating layer, particularly, blurs byacidic rain, scratches caused by sand particles which are blown up by awashing brush and by running. For example, a clear coat which is anover-coating in a car body is often composed of an acrylic resin and amelamine resin, and it becomes clear that the melamine resin causes aproblem of decline in the acid resistance and, there are proposed(JP-A-63221123 Official Gazette and JP-A-63108048 Official Gazette)coatings by a novel crosslinking style not containing the melamineresin. However, the coatings are higher in price compared to amelamine-based thermosetting coating, and include a problem that thoseare poor in adhesion to the melamine-based thermosetting coating.

Of the acrylic resins, an acrylic polyol in which there is copolymerizeda monomer having hydroxyl group is employed in an ordinarytemperature-curable or thermosetting-curable coating in which there isformulated a crosslinking agent which can react with hydroxyl group, forexample, such as a polyisocyanate and a melamine resin. In order to givean adhesion to a coating layer and a gasoline resistance, acrylicmonomers having hydroxyl group are indispensable.

As such the monomers having hydroxyl group, there have beenconventionally employed a hydroxyethyl(meth)acrylate and ahydroxypropyl(meth)acrylate, etc.

However, since the hydroxyl group in an acrylic polyol prepared bycopolymerization of the (meth)acrylates is situated in an exceedinglynear position to a main chain of an acrylic resin structure which isrigid, a reactivity with the crosslinking agent is not sufficient.

For the purpose of improvement thereof, although 4-hydroxybutylacrylateis proposed, it is difficult to say that a reactivity thereof issufficient.

As a method for solving such the problems, in relation to a abrasionresistance, for example, there has been conventionally known(JP-A-64066274 Official Gazette) a coating using a clear coat in whichthere are employed an ε-caprolactone-modified acrylic resin obtained bycopolymerization of an ε-caprolactone-added hydroxyalkyl(meth)acrylatewith other vinyl monomers and a melamine curing agent and, further, foran acidic rain, for example, there has been conventionally known(JP-A-04114069 Official Gazette) a coating using a clear coat in whichthere are simultaneously employed a reaction of carboxylic acid with anepoxy and a reaction of an acrylic resin with a melamine curing agent.

However, since the lactone-modified (meth)acrylate in a technology ofthe JP-A-64066274 Official Gazette has a broad distribution ofcontinuous lactone chains and the number (n) of the continuous lactonechains is large, there is occasionally caused the above-describedproblem that although curing reactivity and flexibility are improved,there lower hardness and acid resistance, etc.

On the other hand, although there is obtained a coating layer having anexcellent acid resistance in a technology of the JP-A-04114066 OfficialGazette, abrasion resistance is insufficient.

Further, there has been known that it is an effective method to elevatea glass transition temperature in a cured coating layer formed from aclear coat which is a most outside surface layer in order to obtain anadvanced acid resistance. However, in the case, there has been a problemthat there is caused an unpreferred situation that there lower not onlythe abrasion resistance in the coating layer but also flexuralresistance and adhesion in recoating. Accordingly, it has been anexceedingly difficult technology to obtain a coating layer which ishighly well-balanced in the acid resistance and abrasion resistance, andwhich is also excellent in the flexural resistance and adhesion inrecoating.

IV

Metal cans have been widely employed as a vessel for filling a varietyof beverages and foods.

Outside surface of the cans is coated in order to prevent corrosion byoutside circumstances, and printed in view of a fine sight, and forshowing contents. In printing and coating of the outside surface of thecans, a size-coating is coated on a metal plate, and then, a whitecoating is coated and, printing is conducted thereon by inks, etc. and aclear coating is coated for finishing. The size-coating and whitecoating are also occasionally omitted. Hitherto, as the clear coatingfor finishing, there has been widely employed an organic solventsolution containing an acrylic/amino-based resin, apolyester/amino-based resin, and an epoxy/amino-based resin, etc.

JP-A-06207137 Official Gazette discloses a water-based coating for anouter surface of cans, which is a coating primarily containing a resinmixture composed of (A) 40-60 parts by weight of an acrylic resin havinga specified composition which has a weight average molecular weight of6,000-15,000 and a glass transition temperature of exceeding 0° C., (B)10-20 parts by weight of an acrylic resin having a specified compositionwhich has a weight average molecular weight of 5,000-50,000 and a glasstransition temperature of not more than 0° C., and (C) 20-50 parts byweight of an amino-plasto resin, and the resins (A) and (B) areneutralized by a base and, the resins (A), (B), and (C) are dissolved ordispersed in water. However, a coating layer obtained from theabove-described technology is not sufficient in hardness.

Publicly-known water-based coatings include two types of awater-dispersed type one and a water-soluble type one, and since thewater-dispersed type one is usually synthesized by an emulsionpolymerization method using a surface active agent, there has been aproblem that the surface active agent remains in a coating layer afterhaving formed the coating layer, and it causes a decline of waterresistance. On the other hand, although there is also a methodsynthesizing a resin containing carboxylic groups in an organic solventsystem without employing the surface active agent and making dipersibleor water-soluble by neutralizing in a volatile base, the water-basedcoating requires an acidic component having an acid value of not lessthan 20 in a basic resin structure, and there has been a drawback ofpoor water resistance and alkali resistance, etc.

A variety of coatings have been proposed and, although there is observedan improvement of water resistance in a coating layer, properties arenot in a level being resistible to a thermally sterilizing treatment(retorting) in 130° C. for 30 minutes.

JP-A-07316489 Official Gazette discloses a water-based coatingcomposition characterized by containing 20-80 parts by weight of awater-based acrylic resin obtained by copolymerization of (i) α,β-ethylenic unsaturated carboxylic acid, (ii) a hydroxyl group-containedmono(meth)acrylate including an ε-caprolactone-modified monomer, (iii)an N-alkoxymethyl(meth)acrylic amide having an alkyl group of a carbonnumber of not more than 4, and an aromatic vinyl monomer which iscopolymerizable with the (i)-(iii) and/or an alkyl(meth)acrylate and10-60 parts by weight of a water-based amino resin. However, waterresistance is not sufficient in the coating composition obtained by theabove-described technology.

Further, a water-based coating composition has been also employed forcoating in cars and home electric appliances.

For example, in recent years, a design value in resin-made parts such asa bumper for cars is elevated by coating the same color as in carbodies. In the case of coating a bumper made from a polypropylene, etc.like a body color, there is firstly coated a primer made from achlorinated polypropylene, etc. in order to ensure adhesion. A coatinglayer is formed by a two coating-one baking method (hereinafter,referred to as a 2C1B method) in which a coating layer of the primer isthermally cured and a coating for a base coat and an over coating arecoated by a wet-on-wet method and those are thermally curedcollectively.

However, there has become problematic a staining in a coating layerwhich is called a rain-blot under the influence of an acidic rain inrecent years. Particularly, in a baked coating layer made from amelamine resin, it is known that an ether bond in the vicinity ofmelamine is broken by the acidic rain, and a stain penetrates therein,resulting in that it becomes difficult to remove the stain by awater-washing level. Accordingly, it must be rubbed off by a compound,etc. and, in the case, there is a problem that a coating layer is alsoshaved off, resulting in that the thickness of the coating layer becomesthinner.

Comparing a coating layer on an outside plate of cars to a coating layeron a bumper, the rain-blot is more readily caused in the coating layeron a bumper, there is a problem that the rain-blot once caused is notapt to be removed compared to the coating layer on an outside plate. Itis thought that it depends upon a crosslinking density. In other words,since the coating layer on an outside plate is cured by heatingconditions such as 140° C. for 30 minutes or so, a crosslinking densityis high. However, in the coating layer on a resin-made bumper, sinceheating temperature is suppressed in 120° C. for 20 minutes or so inorder to prevent deformation, a crosslinking density becomes lowercompared to the coating layer on an outside plate for cars. For thatreason, an acid rain resistance is not sufficient, and it is thoughtthat the above-described difference is caused.

Therefore, it is thought that a blocked polyisocyanate compound isemployed as a crosslinking agent without using a melamine resin.However, curability is poor at a low temperature in a coatingcomposition in which the blocked polyisocyanate compound is employed asa crosslinking agent. For that reason, when the coating composition iscoated on a resin-made bumper, etc., since heating temperature is 120°C. to the utmost, crosslinking density is low, resulting in that therebecome insufficient physical properties such as solvent resistance,staining resistance, and water resistance.

JP-A-11012533 discloses a water-based coating composition comprising aneutralized product of an amino resin-modified polymer in whichstructural units based on the above-described component (a) in thecopolymer composed of (a) radically polymerizable compound having aspecified structural formula, (b) an α,β-ethylenic unsaturatedcarboxylic acid, and (c) other radically polymerizable monomers aremodified by a reaction of hydroxyl group in the units with an aminoresin. However, a coating layer from the composition is not sufficientin retort resistance.

V

As described hereinabove, in recent years, an acrylic-based coating isbecoming important in a coating field and, in a coating layer for cars,durability of a coating layer, particularly, there become problematic arain-blot by an acidic rain, abrasions by sand particles blown up by awashing brush and during driving, and the above-described variousmethods are proposed. However, there have still been the above-describedvarious problems.

On the other hand, although an isocyanate curing system shows anexcellent acid resistance, adhesion, water resistance, and hardness,there is a problem that a pot-life is shorter compared to a melaminecoating and, crosslinking of a resin is insufficient, and abrasionresistance is lower in a coating layer. Although the abrasion resistancecan be improved by employing a modified hydroxy(meth)acrylate, etc. (PCLF, etc.), a pot-life further becomes short by an existing PCL F having along lactone continuous chain length, and there is caused a problem thatit cannot become taken a working time of period.

VI

For the above-described problems in an isocyanate curing system,JP-A-05148313 Official Gazette proposes a coating which possessesvarious properties such as profitability and workability without loss ofa fine spectacle and, moreover, which can also satisfy a corrosionresistance, and which can provide a coating layer for a metal having anadvanced corrosion resistance and, moreover, which primarily contains acoating layer-formable resinous component in which there are employedspecified crosslinked particles which do not cause any problems incorrosion resistance even though a conventional melamine curing agent isemployed. Although the abrasion resistance can be improved by employinga modified hydroxy(meth)acrylate, etc. (PCL F, etc.), the abrasionresistance, the improvement is insufficient by the PCL F having a longlactone continuous chain length.

VII

In a conventional thermosetting coating, there has been employed amelamine resin such as an alkyd melamine resin, an acrylic melamineresin, and an epoxy melamine resin as a crosslinking agent, and an odorfrom the melamine resin has been largely problematic. Further, in anacrylic melamine resin and an alkyd melamine resin which are usuallyemployed as a coating for cars, there are not always sufficientlysatisfied properties such as weatherability, staining resistance, acidicresistance, and a water-repellent property, and an improvement thereofis strongly desired.

As a method for solving the problems, there is proposed a technology(JP-A-01141952 Official Gazette, etc.) concerning a composition which iscured by a crosslinking style using a polyol resin and a hydrolyzablesilyl group-contained resin, and which is quite different from acrosslinking style using a conventional polyol resin and melamine resin.However, there are not still sufficiently satisfied hardness, abrasionresistance, water resistance, and solvent resistance.

VIII

Since a polyalkyleneglycol di(meth)acrylate forms a flexible thin layerafter curing, it is one of exceedingly useful raw materials foremploying as an ink and coating, etc. Further, a low molecular weightone is important also as a reactive diluent in an acrylic resin field.

It is to be noted that in the present invention, an acrylate andmethacrylate are called a (meth)acrylate, and acrylic acid andmethacrylic acid are called a (meth)acrylic acid. However, an acrylicresin and a methacrylic resin are merely called an acrylic resin.

On the other hand, an acrylic resin having carboxylic group (—COOH) iseffective for improving adhesion to a material which includes a resinsuch as a nylon having amino group, and an inorganic compound such as ametal having hydroxyl group and a silica. Further, it is recognized thatit is effective for improving a water-solubility and an aqueous alkalisolution-solubility of an acylic resin, above all, shortening ofdeveloping time of period in an alkali development step and a removingability of uncured portion in the case of forming a pattern usingultraviolet ray-curability.

For that reason, there is desired a carboxylic group-contained acrylatesuch as a carboxylic group-contained lactone acrylate, and there hasbeen desired a method for the preparation thereof which is industriallyand readily operated.

IX

In a binder for employing as an over-coating for cars, a polymer havinghydroxyl group is usually employed in combination with a melamine resincuring agent. However, in a cured thin layer obtained by employing amelamine resin as a curing agent, an acid resistance is usually poor.Accordingly, such the thin layer is apt to be particularly deterioratedby an acidic rain which is recently talked about, resulting in that aproblem is caused in an outer appearance.

It is thought that a poor acid resistance in a thin layer obtained byemploying a melamine resin as a curing agent is caused by a triazinering in the melamine resin. Accordingly, so far as a melamine resin isemployed as a curing agent, a drawback of the poor acid resistance isnot solved.

For example, JP-A-02045577 and JP-A-03287650 Official Gazettes propose anovel coating composition in which a melamine resin is not employed. Inthe coating composition, since a crosslinking is initiated in an esterbond which is produced by a reaction of an acid group with an epoxygroup, an acid resistance is excellent.

However, in the curing system, since functional group concentration ishigher and viscosity is high, it is difficult to prepare a high solidtype coating having a high solid content, and it is required that alarge amount of solvents are employed.

On the other hand, in recent years, there is desired a high solidcoating which does not emit a large amount of solvents in circumstancesin order to reduce a bad influence to circumstances.

JP-A-06166741 Official Gazette discloses a high solid coatingcomposition in which a silicone polymer is employed. However, in theinventions, in order to introduce a hydroxyl group-functional siliconepolymer into a coating composition, an acid-functionalty is given by areaction with an acid anhydride. As a result, there is caused a drawbackthat an amount of functional groups cannot be elevated, and Tg islowered in resins and, Tg cannot be elevated in a coating layer.

On the other hand, JP-B-94041575 Official Gazette discloses a high solidcoating composition containing (a) a polyepoxide and (b) a polyesterpolycarboxylic acid. However, solid content in the coating compositionis not high from a viewpoint of not adversely affecting tocircumstances, resulting in that a coating layer formed is poor in anacid resistance

Further, in an acid-epoxy curing type coating system, a clear coatinglayer when being thermally cured remarkably yellows compared to aconventional melamine type coating system, and it is difficult to designa light color such as a white mica color.

X

As described hereinabove, in recent years, an acrylic-based coating isbecoming important in a coating field, and an acrylic-based coating isbecoming employed in every fields.

In a conventional lactone modified (meth)acrylate, since distribution oflactone continuous chains becomes broad and the number (n) of continuouschain length becomes large, although a curing reactivity and flexibilityare improved, there is occasionally caused a problem of a decline ofhardness and acid resistance.

On the other hand, as radically polymerizable unsaturated monomershaving carboxylic group, there are known (meth)acrylic acid, itaconicacid, maleic acid, β-(meth)acryloyloxyethyl succinic acid,β-meth)acryloyloxyethyl maleic acid, and β-(meth)acryloyloxyethylphthalic acid, etc.

The radically polymerizable unsaturated monomers having carboxylic groupare employed in exceedingly wide range uses as a raw material and anintermediate for a thermosetting coating, an adhesive, an modifier forprocessing papers, a crosslinking agent, and a processing agent forfibers, etc., it is required that a kind of the radically polymerizableunsaturated monomers is carefully selected like being appropriate forrespective uses.

Generally speaking, as a method for synthesizing a polyester unsaturatedmonomer having carboxylic group at a terminal, there are known a methodin which an ω-hydroxycarboxylic acid is allowed to react with aradically polymerizable unsaturated monomers having carboxylic group, amethod in which an α,ω-polyester dicarboxylic acid is allowed to reactwith a radically polymerizable unsaturated monomers having hydroxylgroup, and a method, etc. in which an acid anhydride is allowed to reactwith a radically polymerizable unsaturated monomers having carboxylicgroup and an epoxy compound.

However, the methods include a problem that there are largely producedproducts quite not having a radically polymerizable functinal group orproducts having two radically polymerizable functinal group asby-products.

Further, as another method, there is a method in which a metal salt of aradically polymerizable unsaturated monomers having carboxylic group,for example, sodium acrylate is allowed to react with anω-halogenocarboxylic acid, for example, ε-chlorocaproic acid.

However, in the methods, an ω-halogenocarboxylic acid which is a rawmaterial is prepared through many steps for the preparation, and aplurality of steps are required for introducing two or more pieces of aradically polymerizable functional groups and, further, there is alsorequired a step for separating a halogenated metal salt by-produced, asa result, an industrial preparation method is not still actualized.

As a method for intending to improve such the drawbacks, for example,JP-A-60067446 proposes a method. In the method, a radicallypolymerizable unsaturated monomers having carboxylic group is allowed toreact with ε-caprolactone under the presence of an acidic catalyst toprepare a caprolactone polyester unsaturated monomer, and a fair resultis obtained as an industrial method for the preparation. However, anacrylic resin prepared using the monomer often shows tackiness, and itincludes a problem as an electric material.

Purpose of the present invention I is to provide ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactone which is employed as an industrial finishing agent (a coating)having a high quality and which is well-balanced in a variety ofphysical properties in a coating layer, for example, through using as acomonomer in a polymerization reaction with other monomers, and toprovide an acrylic polyol resin using the composition.

Purpose of the present invention II is to provide a method for thepreparation of the composition.

Purpose of the present invention III is to provide a curable typecoating composition in which an acid resistance is elevated even thoughin a melamine type which is low in price, and which is well-balanced inabrasion resistance and the acid resistance.

Purpose of the present invention IV is to provide a melamine-curabletype water-based coating composition which is excellent in hardness,water resistance, restoring resistance, and processability, etc. of acoating layer, and which is excellent for cars, home electricappliances, and cans for beverages and foods.

Purpose of the present invention V is to provide an isocyanate systemcurable type coating composition which has a sufficient pot-life and, inwhich a problem of abrasion resistance is solved while maintaining anexcellent acid resistance, adhesion, water resistance, and hardness.

Purpose of the present invention VI is to provide an isocyanate systemcurable type coating composition which has a sufficient pot-life and, inwhich a problem of abrasion resistance is solved while maintainingexcellent acid resistance, adhesion, water resistance, and hardness.

Purpose of the present invention VII is to provide a thermosetting resincomposition in which a problem of the above-described acid resistanceand odor is solved which are important in a coating for cars, and inwhich hardness and abrasion resistance, water resistance, and solventresistance are improved by elevating a crosslinking density, and toprovide a top-coat clear coating using the composition.

Purpose of the present invention VIII is to provide anindustrially-feasible method for the preparation of a carboxylicgroup-contained acrylate composition modified by a small amount oflactones.

Purpose of the present invention IX is to provide a high solid curableresin composition in which the above-described problems are solved and,which is capable of forming a thin layer which is excellent in acidresistance to an acid rain, abrasion resistance, yellowing resistance,and outer appearance, and to provide a method for coating (hereinafter,also occasionally referred to as a method for forming a coating layer)using the composition.

Purpose of the present invention X is to provide a polyester unsaturatedmonomer composition modified by a small amount of lactone which isobtained through an addition reaction of lactone by decreasing lactonechains, which is employed as an industrial finishing agent (a coating)having a high quality which is well-balanced in various physicalproperties of a coating layer by employing as a comonomer in apolymerization reaction with other monomers, and to provide a method forthe preparation thereof, and to provide an acrylic resin using thereofwhich does not show tackiness so much.

DISCLOSURE OF THE INVENTION

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention I, found out that theabove-described requirements can be satisfied by ahydroxyalkyl(meth)acrylate composition in which there is decreased aproportion of monomers containing two or more continuous chains (n≧2) oflactones by allowing to react in a large reaction ratio (the former molnumber/the latter mol number) of a hydroxyalkyl(meth)acrylate withrespect to a lactone monomer, and the present invention has beencompleted.

That is, No. 1 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones, in which a proportion of monomers having two or morecontinuous chains (n≧2) of lactones is less than 50% (area % by GPC)which is represented by general formula (1) described below,

(in the formula, R, R¹, R², and R³ are independently a hydrogen or amethyl group, j is an integer of 2-6, xn pieces of R⁴ and R⁵ areindependently a hydrogen or an alkyl group having a carbon number of1-12, “x” is 4-7, “n” is 0 or an integer of not less than 1, and anaverage value of “n” in the composition is not less than 0.3 to lessthan 1.0).

Further, No. 2 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in No. 1 of the present invention I, in which thehydroxyalkyl(meth)acrylate is a hydroxyethyl (meth)acrylate.

Still further, No. 3 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in No. 1 of the present invention I, in which thelactone monomer which is employed as a raw material is ε-caprolactoneand/or valerolactone.

Furthermore, No. 4 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in No. 1 of the present invention I, in which thecontent of the lactone monomer remained in the composition is 0-10% byweight.

Besides, No. 5 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in No. 1 of the present invention I in which thecontent of the hydroxyalkyl(meth)acrylate remained in the composition isnot less than 20% by weight and not more than 50% by weight.

Also, No. 6 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in No. 1 of the present invention I, in which thecontent of a di(meth)acrylate which is a by-product in the compositionis not more than 2% by weight.

And also, No. 7 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in No. 1 of the present invention I, in which thecontent of by-products is not more than 10% by weight in thecomposition, which are produced by side reactions such as a Michaelsaddition, an acrylic polymerization, a transesterification, and otherside reactions.

And also, No. 8 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in any one of Nos. 1-7 of the present invention I,in which the amount of a catalyst to be employed in the ring-openingpolymerization for the preparation of the composition is less than 1000ppm (by weight) based on total amount of materials to be fed.

Also, No. 9 in the present invention I provides ahydroxyalkyl(meth)acrylate composition modified by a small amount oflactones as described in any one of Nos. 1-8 of the present invention I,in which a polymerization inhibitor is not more than 1% by weight basedon total amount, which is employed for the hydroxyalkyl(meth)acrylate inthe ring-opening polymerization for the preparation of the composition.

And also, No. 10 in the present invention I provides an acrylic polyolresin which is obtained using a hydroxyalkyl (meth)acrylate compositionmodified by a small amount of lactones as described in any one of Nos.1-9 of the present invention I as a component for polymerization.

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention II, found out that therecan be obtained a lactone-modified hydroxyalkyl(meth)acrylatecomposition in which lactone continuous chains are decreased by allowingto react a hydroxyalkyl(meth)acrylate with a lactone in a reaction molarratio of more than 1 (mol number of the former/mol number of thelatter), and the present invention has been completed.

That is, No. 1 in the present invention II provides a method for thepreparation of a lactone-modified hydroxyalkyl (meth)acrylatecomposition in which a proportion of monomers having not less than 2continuous chains (n≧2) of lactones is less than 50% by mol (GPC area%), characterized in that a hydroxyalkyl (meth)acrylate is allowed toreact with a lactone in a reaction molar ratio of more than 1 in thecase of preparing the polylactone-modified hydroxyalkyl(meth)acrylatethrough allowing to react the hydroxyalkyl(meth)acrylate with a lactonemonomer by ring-opening polymerization according to a reactionrepresented by a general formula (2) described below.

(in the formula, R, R¹, R², and R³ are independently a hydrogen or amethyl group, “j” is an integer of 2-6, xn pieces of R⁴ and R⁵ areindependently a hydrogen or an alkyl group having a carbon number of1-12, “x” is 4-7, “n” is 0 or an integer of not less than 1, and anaverage value of “n” in the composition is not less than 0.3 to lessthan 1.0).

Further, No. 2 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in No. 1 of the present inventionII, in which the hydroxyalkyl(meth)acrylate is hydroxyethylacrylate orhydroxyethylmethacrylate.

Still further, No. 3 in the present invention II provides a method forthe preparation of a hydroxyalkyl(meth)acrylate composition modified bya small amount of lactones as described in No. 1 or 2 of the presentinvention II, in which the lactone monomer is ε-caprolactone and/orvalerolactone.

Furthermore, No. 4 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in any one of Nos. 1-3 of thepresent invention II in which an average value of n is not less than0.35 and not more than 1.0.

Besides, No. 5 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in any one of Nos. 1-3 of thepresent invention II, in which the content of the lactone monomerremained in the composition is 0-10% by weight.

Also, No. 6 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in any one of Nos. 1-3 of thepresent invention II in which the content of thehydroxyalkyl(meth)acrylate remained in the composition is not less than20% by weight and not more than 50% by weight.

And also, No. 7 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in any one of Nos. 1-3 of thepresent invention II, in which the content of a di(meth)acrylate whichis a by-product in the composition is not more than 2% by weight.

And also, No. 8 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in any one of Nos. 1-3 of thepresent invention II, in which the content of by-products is not morethan 10% by weight in the composition, which are produced by sidereactions such as a Michaels addition, an acrylic polymerization, atransesterification, and other side reactions.

And also, No. 9 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in any one of Nos. 1-8 of thepresent invention II, in which the amount of a catalyst to be employedin the reaction of the lactone with the hydroxyalkyl(meth)acrylate isless than 1000 ppm (by weight) based on total amount of materials to befed.

And also, No. 10 in the present invention II provides a method for thepreparation of a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones as described in any one of Nos. 1-9 of thepresent invention II, in which the content of an inhibitor inpolymerization of the hydroxyalkyl(meth)acrylate with the lactones isnot more than 1% by weight based on total amount of materials to be fed.

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention III, found out that theabove-described requirement can be satisfied by a curable resincomposition containing 0.5-80 parts by weight of an acrylic polyol resin(A) obtained using a hydroxyalkyl(meth)acrylate composition (a) in whicha proportion of monomers having not less than 2 continuous chains (n≧2)of lactones is decreased and 0.5-50 parts by weight of a melamine resin(III-B) as essential components, and the present invention has beencompleted.

That is, No. 1 in the present invention III provides a curable resincomposition containing 0.5-80 parts by weight of an acrylic polyol resin(A) obtained using a hydroxyalkyl(meth)acrylate composition (a) modifiedby a small amount of lactones in which a proportion of monomers havingnot less than 2 continuous chains (n≧2) of lactones is less than 50%(GPC area %) as polymerizing components and 0.5-50 parts by weight of amelamine resin (B) [total of the (A) and (B) does not exceed 100 partsby weight].

Further, No. 2 in the present invention III provides a curable resincomposition as described in No. 1 of the present invention III, in whichthe hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactones is obtained using a hydroxyethyl(meth)acrylate.

Still further, No. 3 in the present invention III provides a curableresin composition as described in No. 1 or 2 of the present inventionIII, in which the hydroxyalkyl(meth)acrylate composition (a) modified bya small amount of lactones is obtained using ε-caprolactone,δ-valerolactone, γ-butyrolactone, or a mixture thereof as lactonemonomers.

Besides, No. 4 in the present invention III provides a curable resincomposition as described in any one of Nos. 1-3 of the present inventionIII, in which the acrylic polyol resin (A) is composed of 5-70 parts byweight of the hydroxyalkyl(meth)acrylate composition (a) modified by asmall amount of lactones, 0-90 parts by weight of an alkyl(meth)acrylatehaving a carbon number of 1-20, 0-30 parts by weight of a (meth)acrylicacid, and 0-40 parts by weight of other polymerizable unsaturatedmonomer.

Also, No. 5 in the present invention III provides a curable resincomposition as described in any one of Nos. 1-4 of the present inventionIII, in which the acrylic polyol resin (A) has a hydroxyl group value of5-250 and a number average molecular weight of 3,000-300,000.

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention IV, found out that theabove-described problems can be solved by using a melamine-curable typewater-based coating composition composed of an acrylic polyol resin (A)obtained by a specified hydroxyalkyl(meth)acrylate composition (a)modified by a small amount of lactones and an amino-plasto resin (B),and the present invention has been completed.

That is, No. 1 in the present invention IV provides a melamine-curabletype water-based coating composition containing 5-30 parts by weight ofan acrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylatecomposition (a) modified by a small amount of lactones represented bythe above-described general formula (1), in which a proportion ofmonomers having not less than 2 continuous chains (n≧2) of lactones isless than 50% (GPC area %) as polymerizing components and 10-60 parts byweight of an amino-plasto resin (IV-B).

No. 2 in the present invention IV provides a melamine-curable typewater-based coating composition as described in No. 1 of the presentinvention IV, characterized in that the acrylic polyol resin (A) iscomposed of (i) 3-40% by weight of the hydroxyalkyl (meth)acrylatecomposition (a) modified by a small amount of lactones, (ii) 1-20% byweight of α,β-unsaturated carboxylic acid, (iii) 1-25% by weight of anN-alkoxymethyl(meth)acrylate having a carbon number of 1-6 in an alkylgroup, and (iv) an aromatic vinyl monomer and an alkyl(meth)acrylatewhich are contained in an amount that 100% by weight minus the totalweight of the above components (i), (ii), and (iii).

No. 3 in the present invention IV provides a melamine-curable typewater-based coating composition as described in No. 1 or 2 of thepresent invention IV, in which the acrylic polyol resin (A) has a numberaverage molecular weight of 2,000-50,000, a hydroxyl group value of10-150, and a Tg point of 0-60° C.

No. 4 in the present invention IV provides a melamine-curable typewater-based coating composition as described in any one of Nos. 1-3 ofthe present invention IV, in which the amino-plasto resin (IV-B) is atleast one of a melamine resin (j), a guanamine resin (k) selected frombenzoguanamine, spyroguanamine, acetoguanamine, and phthaloguanamine,and/or a melamine-guanamine cocondensed resin (l).

No. 5 in the present invention IV provides a melamine-curable typewater-based coating composition as described in any one of Nos. 1-4 ofthe present invention IV, which is employed for cars, home electricappliances, and cans for beverages and foods.

The present inventors, as a result of an intensive investigation forattaining the purpose of the present invention V, found out that theabove-described requirement can be satisfied by a curable resincomposition essentially containing 50-90 parts by weight of an acrylicpolyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition(a) in which a proportion of monomers having not less than 2 continuouschains (n≧2) of lactones is reduced and which is obtained by a largereaction molar ratio of a hydroxyalkyl(meth)acrylate with lactonemonomers (the former mol number/the latter mol number), and 10-50 partsby weight of a polyisocyanate compound (V-B), and the present inventionhas been completed.

That is, No. 1 in the present invention V provides a curable resincomposition containing 50-90 parts by weight of an acrylic polyol resin(V-A) obtained using a hydroxyalkyl(meth)acrylate composition (a)modified by a small amount of lactones which is represented by theabove-described general formula (1) in which a proportion of monomershaving not less than 2 continuous chains (n≧2) of lactones is less than50% (GPC area %) as polymerizing components and 50-10 parts by weight ofa polyisocyanate compound (V-B) [total of the (V-A) and (V-B) does notexceed 100 parts by weight].

No. 2 in the present invention V provides a curable resin composition asdescribed in No. 1 of the present invention V, in which the acrylicpolyol resin (V-A) is composed of 5-65% by weight of thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones, 0-30% by weight of a vinyl monomer having hydroxyl group,0.1-20% by weight of a polyester resin having a copolymerizableunsaturated group, and other vinyl monomers (residual weight).

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention VI, found out that theabove-described requirement can be satisfied by a curable resincomposition essentially containing 0.5-80 parts by weight of an acrylicpolyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition(a) modified by a small amount of lactones, and which is obtained by alarge reaction molar ratio of a hydroxyalkyl(meth)acrylate with lactonemonomers (the former mol number/the latter mol number), and in which aproportion of monomers having not less than 2 continuous chains (n≧2) oflactones is reduced, and 0.5-50 parts by weight of a polyisocyanatecompound (C), and the present invention has been completed.

That is, No. 1 in the present invention VI provides a curable resincomposition containing 0.5-80 parts by weight of an acrylic polyol resin(VI-A) having carboxylic group and a functional group obtained byallowing to react a hydroxyalkyl(meth)acrylate composition (a) modifiedby a small amount of lactones represented by the general formula (1)described in claim 1 in which a proportion of monomers having not lessthan 2 continuous chains (n≧2) of lactones is less than 50% (GPC area %)with a vinyl monomer having carboxylic group and other vinyl monomers,and 0.5-50 parts by weight of a polyisocyanate compound (VI-B) [total ofthe (VI-A) and (VI-B) does not exceed 100 parts by weight] as essentialcomponents.

Further, No. 2 of the present invention VI provides a curable resincomposition as described in No. 1 of the present invention VI, in whichthe acrylic polyol resin (VI-A) is a vinyl copolymer having carboxylicgroup and a functional group obtained by allowing to react a reactionproduct of a hydroxyl group-contained resin obtained by copolymerizing ahydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones with a (meth)acrylic anhydride, and then, by allowing to reactthe reaction product with a vinyl-based monomer having carboxylic groupand other vinyl-based monomers.

Still further, No. 3 of the present invention VI provides a curableresin composition as described in No. 2 of the present invention VI, inwhich the acrylic polyol resin (VI-A) is a resin obtained using thehydroxyl group-contained resin in the No. 2 of the present invention VIand at least one selected from a urethane resin having hydroxyl groups,an epoxy resin having hydroxyl groups, a cellulose derivative havinghydroxyl groups, and a polyester resin having hydroxyl groups as theresin having hydroxyl groups.

Furthermore, No. 4 of the present invention VI provides a curable resincomposition as described in No. 2 of the present invention VI, in whichthe acrylic polyol resin (VI-A) is a resin obtained using the hydroxylgroup-contained resin in the No. 2 of the present invention VI and aurethane resin having hydroxyl groups as the resin having hydroxylgroups.

Besides, No. 5 in the present invention VI provides a curable resincomposition as described in any one of Nos. 1-4 of the present inventionVI, in which the polyisocyanate compound (VI-B) is a polyisocyanatecompound containing an epoxy resin.

Also, No. 6 in the present invention VI provides a curable resincomposition as described in any one of Nos. 1-5 of the present inventionVI, in which the hydroxyalkyl(meth)acrylate composition (a) modified bya small amount of lactones is a product obtained usinghydroxyethyl(meth)acrylate.

And also, No. 7 of the present invention VI is a coating characterizedby containing (i) crosslinked particles obtained by dispersing a mixtureof the acrylic polyol resin (VI-A) with the polyisocyanate compound(VI-B) into a water-based medium and by crosslinking thereof, or (ii)composite-type crosslinked particles composed of aurethane-urea/ethylene-based resin obtained through polymerizingpolymerizable ethylene-based unsaturated compounds containing thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones in water in which crosslinked urethane-urea particles aredispersed, as resin components for forming a thin layer.

And also, No. 8 of the present invention VI is a coating as described inNo. 7 of the present invention VI characterized by containing more than50% by weight of crosslinked particles having particle diameter of notmore than 1 m and, moreover, an average molecular weight betweencrosslinking points of a range of 300-2,000, as resin components forforming a thin layer.

And also, No. 9 of the present invention VI is a coating as described inNo. 7 or 8 of the present invention VI, in which the crosslinkedparticles have a thin layer-formable temperature of not more than 100°C.

And also, No. 10 of the present invention VI is a coating as describedin any one of Nos. 7-9 of the present invention VI, in which the contentof the crosslinked particles is not less than 70% in the resincomponents for forming a thin layer.

And also, No. 11 of the present invention VI is a coating as describedin any one of Nos. 7-10 of the present invention VI, characterized bycontaining 1-25% by weight of a crosslinking agent together with thecrosslinked particles as the resin components for forming a thin layer.

And also, No. 12 of the present invention VI is a coating as describedin any one of Nos. 7-11 of the present invention VI, characterized byfurther containing a thin layer-formable resin having a reactive groupother than the crosslinked particles as the resin components for forminga thin layer.

And also, No. 13 of the present invention VI is a coating as describedin any one of Nos. 7-12 of the present invention VI, in which thecrosslinked particles contain pigments in an inside thereof.

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention VI, found out that theproblems can be solved by using a curable resin composition whichcomprises an acrylic polyol resin (VII-A) having hydroxyl groupscomposed of a hydroxyalkyl(meth)acrylate composition (a) modified by asmall amount of lactones which has hydroxyl group at a terminal, and anacrylic copolymer (VII-B) having an alkoxysilyl group, and the presentinvention has been completed.

That is, No. 1 in the present invention VII provides a thermosettingresin composition which contains at least 2-50 parts by weight of anacrylic polyol resin (VII-A) containing a hydroxyalkyl(meth)acrylatecomposition (a) modified by a small amount of lactones represented bythe general formula (1) in which a proportion of monomers having notless than 2 continuous chains (n≧2) of lactones is less than 50% (GPCarea %) as a polymerizable component, and 30-80 parts by weight of anacrylic copolymer (VII-B) having an alkoxysilyl group [total of the(VII-A) and (VII-B) does not exceed 100 parts by weight], aspolymerizable components.

No. 2 of the present invention VII provides a thermosetting resincomposition as described in No. 1 of the present invention VII, in whichthe acrylic polyol resin (VII-A) further has at least one kind selectedfrom an acid anhydride group, an epoxy group, amino group, andcarboxylic group.

No. 3 of the present invention VII provides a thermosetting resincomposition as described in No. 1 or 2 of the present invention VII, inwhich the acrylic copolymer (VII-B) having an alkoxysilyl group has agroup represented by general formula (VII-3) described below,

(in the formula, R⁶ represents an alkyl group having a carbon number of1-10, R⁷ and R⁸ are a hydrogen atom or a monovalent hydrocarbon groupselected from an alkyl group, an aryl group, and an aralkyl group whichhave a carbon number of 1-10, “a” is the number of a substituted group,and it represents an integer of 0, 1, or 2).

No. 4 of the present invention VII provides a thermosetting resincomposition as described in No. 3 of the present invention VII, in whichthe acrylic copolymer (VII-B) having an alkoxysilyl group further has atleast one kind selected from an acid anhydride group, an epoxy group,amino group, and carboxylic group.

No. 5 of the present invention VII provides a thermosetting resincomposition as described in No. 3 or 4 of the present invention VII, inwhich the acrylic copolymer (VII-B) having an alkoxysilyl group has anumber average molecular weight of 1,000-30,000.

No. 6 of the present invention VII provides a thermosetting resincomposition as described in any one of Nos. 3-5 of the present inventionVII, in which the acrylic copolymer (VII-B) having an alkoxysilyl groupcontains 5-90% by weight of an alkoxysilyl group-contained monomer(VII-b) having a polymerizable unsaturated double bond as a polymerizingcomponent.

No. 7 of the present invention VII provides a thermosetting resincomposition containing 0.1-20 parts by weight of a catalyst (VII-C) forcuring based on 100 parts by weight of the thermosetting resincomposition as described in any one of Nos. 1-6 of the present inventionVII.

No. 8 of the present invention VII provides a thermosetting resincomposition as described in No. 7 of the present invention VII, in whichthe catalyst (VII-C) for curing is an organic tin compound, an acidicphosphate, a mixture or a reaction product of the acidic phosphate withan amine, a saturated or unsaturated polycarboxylic acid, a saturated orunsaturated polycarboxylic anhydride, a reactive silicone compound, anorganic titanate compound, an organic aluminum compound, or a mixturethereof.

No. 9 of the present invention VII provides a top coat clear coatingessentially containing a thermosetting resin composition as described inNos. 1-8 of the present invention VII.

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention VIII, found out thatthere can be industrially and advantageously prepared a carboxylicgroup-contained acrylate monomer modified by small amount of lactones byallowing to react a hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones which has hydroxyl group at a terminal with acarboxylic acid or an anhydride thereof, and the present invention hasbeen completed.

That is, No. 1 of the present invention VIII provides a method for thepreparation of a carboxylic group-contained acrylate composition (a′)modified by a small amount of lactones represented by a general formula(VIII-3) described below by allowing to react thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones represented by the above-described general formula (1) in whicha proportion of monomers having not less than 2 continuous chains (n≧2)of lactones is less than 50% (GPC area %) with a carboxylic acid oranhydride (VIII-b) thereof represented by a general formula (VIII-2)described below,

(in the formula, R, R¹, R², and R³ are independently a hydrogen or amethyl group, “j” is an integer of 2-6, xn pieces of R⁴ and R⁵ areindependently a hydrogen atom or an alkyl group having a carbon numberof 1-12, “x” is 4-7, “n” is 0 or an integer of not less than 1, anaverage value of “n” in the composition is not less than 0.3 to lessthan 1.0, R⁹ is a residual group of a carboxylic acid, and “m” is aninteger of 1-3).

No. 2 of the present invention VIII provides a method for thepreparation of a carboxylic group-contained acrylate composition (a′)modified by a small amount of lactones as described in No. 1 of thepresent invention VIII, characterized in that a reaction of thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones with the carboxylic acid or anhydride (VIII-b) thereof isconducted at a range of 40-160° C.

No. 3 of the present invention VIII provides a method for thepreparation of a carboxylic group-contained acrylate composition (a′)modified by a small amount of lactones as described in No. 1 or 2 of thepresent invention VIII, characterized in that a reaction of thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones with the carboxylic acid or anhydride thereof (VIII-b) isconducted under the presence of oxygen and a polymerization inhibitor.

No. 4 of the present invention VIII provides a method for thepreparation of a carboxylic group-contained acrylate composition (a′)modified by a small amount of lactones as described in any one of Nos.1-3 of the present invention VIII, characterized in that 0.9-1.1 mol ofthe carboxylic acid or anhydride (VIII-b) thereof is allowed to reactwith 1 mol of the hydroxy(meth)acrylate composition (a) modified by asmall amount of lactones.

The present inventor found out that the purpose of the present inventionIX can be attained by using a resin composition comprising an acrylicpolycarboxylic acid resin (A′) containing a carboxylic group-containedacrylate composition (a′) modified by a small amount of lactones as apolymerizing component and a polyoxide (IX-B), and the present inventionhas been completed.

That is, No. 1 of the present invention IX provides a curable resincomposition comprising 10-70 parts by weight of an acrylicpolycarboxylic acid resin (A′) containing the carboxylic group-containedacrylate composition (a′) modified by a small amount of lactonesrepresented by the above-described general formula (VIII-3) in which aproportion of monomers having not less than 2 continuous chains (n≧2) oflactones is less than 50% (GPC area %) as a polymerizing component and10-80 parts by weight of a polyepoxide (IX-B).

No. 2 of the present invention IX provides a curable resin compositionas described in No. 1 of the present invention IX, characterized in thatthe carboxylic group-contained hydroxy(meth)acrylate composition (a′)modified by a small amount of lactones is obtained by allowing to reactthe hydroxyalkyl(meth)acrylate composition modified by a small amount oflactones represented by the above-described general formula (1) in whicha proportion of monomers having not less than 2 continuous chains (n≧2)of lactones is less than 50% (GPC area %) with the carboxylic acid orthe anhydride thereof represented by the above-described general formula(VIII-2).

No. 3 of the present invention IX provides a curable resin compositionas described in No. 2 of the present invention IX, characterized in thatthe carboxylic group-contained hydroxy(meth)acrylate composition (a′)modified by a small amount of lactones is obtained by allowing to react0.9-1.1 mol of the carboxylic acid or the anhydride thereof with respectto 1 mol of the hydroxy(meth)acrylate composition (a) modified by asmall amount of lactones.

No. 4 of the present invention IX provides a curable resin compositionas described in any one of Nos. 1-3 of the present invention IX,characterized in that the acrylic polycarboxylic acid resin (A′) is acopolymer of 5-80% by weight of a carboxylic group-contained ethylenicunsaturated monomer with 20-95% by weight of an ethylenic unsaturatedmonomer not having carboxylic group, provided that the ratio of thecarboxylic group-contained hydroxy(meth)acrylate composition (a′)modified by a small amount of lactones is 5-50% by weight in the acrylicpolycarboxylic acid resin (A′), and the copolymer has at least twocarboxylic groups on average in the molecule and an acid value of 5-300mg KOH/g-solid and a number average molecular weight of 500-8000.

No. 5 of the present invention IX provides a curable resin compositionas described in any one of Nos. 1-4 of the present invention IX,characterized in that terminal carboxylic groups in the acrylicpolycarboxylic acid resin (A′) are an acrylic polycarboxylic acid resin(bA′) blocked by a blocking group which can discharge carboxylic groupsby heat and/or water.

No. 6 of the present invention IX provides a curable resin compositionas described in any one of Nos. 1-5 of the present invention IX,characterized in that the polyepoxide (IX-B) is an acrylic polyepoxidehaving an epoxy equivalent of 50-700 and a number average molecularweight of 200-10000.

No. 7 of the present invention IX provides a curable resin compositionas described in any one of Nos. 1-6 of the present invention IX,characterized in that the polyepoxide (IX-B) is a polyepoxide havinghydroxyl group and an epoxy group which is obtained by copolymerizationof 5-70% by weight of (i) a hydroxyl group-contained ethylenicunsaturated monomer having a structure represented by a formula (4)described below with 10-60% by weight of (ii) an epoxy group-containedethylenic unsaturated monomer and optionally 0-85% by weight of (iii) anethylenic unsaturated monomer not having an epoxy group,

[in the formula, R is a hydrogen atom or a methyl group, and X is anorganic chain shown by formula (5) described below,

—O—Y—(OCO—(CH₂)_(m)—)_(q)—  (5)

(in the formula, Y is a linear or branched alkylene group having acarbon number of 2-8, “m” is an integer of 3-7, and “q” is an integer of0-4),

or an organic chain shown by formula (6) described below,

(in the formula, R is a hydrogen atom or a methyl group, and n is aninteger of 2-50)].

No. 8 of the present invention IX provides a curable resin compositionas described in any one of Nos. 1-7 of the present invention IX, andwhich further contains 0.1-10 parts by weight of an antioxidant (IX-C).

No. 9 of the present invention IX provides a curable resin compositionas described in any one of Nos. 1-8 of the present invention IX, andwhich further contains 5-70 parts by weight of a polyesterpolycarboxylic acid (IX-D) having an acid value of 30-350mg-KOH/g-solid.

No. 10 of the present invention IX provides a curable resin compositionas described in any one of Nos. 1-9 of the present invention IX, andwhich further contains 0.1-10 parts by weight of crosslinked resinparticles (IX-E).

No. 11 of the present invention IX provides a clear coating compositioncontaining a curable resin composition as described in any one of Nos.1-10 of the present invention IX as a binder.

No. 12 of the present invention IX provides a method for coating whichincludes a step in which a water-based or a solvent-based base coatingis coated on a substrate coated by under-coating or internally-coating;a step in which a clear coating composition of No. 1 in the presentinvention IX is coated on the base coating layer without curing; and astep in which a layer of the base coating and a layer of the clearcoating are cured by heating.

In the above descriptions, part is part by weight.

The present inventor, as a result of an intensive investigation forattaining the purpose of the present invention X, found out that theabove-described requirement can be satisfied by a polyester unsaturatedmonomer composition modified by a small amount of lactones, in which aproportion of monomers having not less than 2 continuous chains (n≧2) oflactones is decreased by a large reaction molar ratio (the former molnumber/the latter mol number) of a carboxylic group-containedpolymerizable unsaturated monomer, and the present invention has beencompleted.

That is, No. 1 of the present invention X provides a polyesterunsaturated monomer composition modified by a small amount of lactones,in which a proportion of monomers having not less than 2 continuouschains (n≧2) of lactones is less than 50% (GPC area %) with respect tototal of polymerizable unsaturated monomers containing carboxylic group,and which are obtained by a ring-opening polymerization of a lactonemonomer.

No. 2 of the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin No. 1 of the present invention X, in which the polymerizableunsaturated monomers containing carboxylic group are at least one kindselected from a group consisting of a (meth)acrylic acid, itaconic acid,β-(meth)acryloyloxyethyl succinic acid, β-(meth)acryloyloxyethyl maleicacid, β-(meth)acryloyloxyethyl phthalic acid, maleic acid, a monoalkylmaleate (a carbon number in an alkyl group is 1-12), tetrahydrophthalicacid, and an anhydride thereof.

No. 3 of the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin No. 2 of the present invention X, in which the polymerizableunsaturated monomers containing carboxylic group are a (meth)acrylicacid, and which is obtained by a reaction represented by formula (11)described below,

(in the formula, R and R¹ are independently a hydrogen atom or a methylgroup, xn pieces of R⁴ and R⁵ are independently a hydrogen atom or analkyl group having a carbon number of 1-12, “x” is 4-7, “n” and “n” inthe composition are 0 or an integer of not less than 1, and an averagevalue of “n” in the composition is not less than 0.3 to less than 1.0).

No. 4 of the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin any one of Nos. 1-3 of the present invention X, in which the lactonemonomer is a lactone having 5, 6, 7 and/or 8-members ring.

No. 5 of the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin any one of Nos. 1-4 of the present invention X, in which the lactonemonomer is ε-caprolactone and/or valerolactone.

No. 6 of the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin any one of Nos. 1-5 of the present invention X, characterized in thatthe proportion of monomers having not less than 2 continuous chains(n≧2) of lactones is less than 40% (GPC area %).

No. 7 in the present invention I provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin any one of Nos. 1-6 of the present invention X, in which the contentof residual lactone monomers is 0-10% by weight.

No. 8 in the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin any one of Nos. 1-7 of the present invention X, in which the contentof the residual polymerizable unsaturated monomers containing carboxylicgroup is more than 20% by weight and not more than 50% by weight.

No. 9 in the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactones as describedin any one of Nos. 1-8 of the present invention X, in which the contentof a di(meth)acrylate of the polymerizable unsaturated monomerscontaining carboxylic group which is a by-product is not more than 2% byweight.

No. 10 in the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactone as describedin any one of Nos. 1-9 of the present invention X, in which the contentof by-products produced by side reactions such as a Michaels addition,an acrylic polymerization, a transesterification, and other sidereactions is not more than 10% by weight.

No. 11 in the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactone as describedin any one of Nos. 1-10 of the present invention X, in which the amountof a catalyst to be employed in the ring-opening polymerization is lessthan 1000 ppm by weight based on total amount of materials to be fed.

No. 12 in the present invention X provides a polyester unsaturatedmonomer composition modified by a small amount of lactone as describedin any one of Nos. 1-11 of the present invention X, in which apolymerization inhibitor is not more than 1% by weight based on totalamount to be fed, which is employed for a (meth)acrylic acid in thering-opening polymerization.

No. 13 in the present invention X provides a method for the preparationof a polyester unsaturated monomer composition modified by a smallamount of lactone, in which 0.3-less than 1.0 mol of a lactone monomeris polymerized by ring-opening with respect to 1 mol of a radicallypolymerizable unsaturated monomers containing carboxylic group, and aproportion of monomers having not less than 2 continuous chains (n≧2) oflactones is adjusted to less than 50%.

No. 14 in the present invention X provides a method for the preparationof a polyester unsaturated monomer composition modified by a smallamount of lactone as described in No. 13 of the present invention X, inwhich an acidic catalyst is a Lewis acid or a Br nsted acid.

No. 15 in the present invention X provides an acrylic resin using apolyester unsaturated monomer composition modified by a small amountlactone as described in any one of Nos. 1-12 of the present invention X.

No. 16 in the present invention X is a method for the preparation ofpolyester unsaturated monomer composition modified by a small amount oflactone, characterized in that 0.3-less than 1.0 mol of a lactonemonomer is polymerized by ring-opening with respect to 1 mol of aradically polymerizable unsaturated monomers containing carboxylic groupusing a stannous halide, monobutyltin tris-2-ethylhexanate, stannousoctoate, dibutyltin dilaurate, or a mixture thereof as a catalyst,followed by separating unreacted radically polymerizable unsaturatedmonomers containing carboxylic group.

No. 17 in the present invention X is a method for the preparation of apolyester unsaturated monomer composition modified by a small amount oflactone as described in claim 12, in which the catalyst to be employedin the ring-opening polymerization is less than 1000 ppm by weight basedon total amount of materials to be fed.

By the present invention, there can be prepared a polyester unsaturatedmonomer modified by a small amount of lactone having the same number ofa radically polymerizable functional group as in the radicallypolymerizable unsaturated monomer having carboxylic group which isemployed as a raw material, and in which an average addition amount oflactones is 0.35 to not more than 1.0 mol.

Particularly, in the case that there are employed, for example, acrylicacid and methacrylic acid as the radically polymerizable unsaturatedmonomer having carboxylic group, there can be prepared the polyesterunsaturated monomer modified by a small amount of lactone whichessentially contains 1 piece of a radically polymerizable functionalgroup without producing a compound not having a radically polymerizablefunctional group at all and a compound having two or more pieces of aradically polymerizable functional group.

The polyester unsaturated monomer modified by a small amount of lactoneobtained has a reactive carboxylic group at one terminal thereof and,further, it has a feature that there is a radically polymerizableunsaturated group at a position which exists far apart from thecarboxylic group.

Further, in the acrylic resin composition using the polyesterunsaturated monomer modified by a small amount of lactone of the presentinvention, since tackiness can be removed by elevating Tg of the resincomposition, it is particularly useful in an electric material field,etc.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an example of a continuous chain distribution ofε-caprolactone obtained from a gel permeation chromatographic (GPC)analysis in Examples 1-4 and Comparative Examples 1-5.

FIG. 2 shows a relationship of feeding ratio of ε-caprolactone/HEMA witha continuous chain distribution ratio of ε-caprolactone from a GPCanalysis in Examples 5-6 and Comparative Examples 7-11.

BEST MODE FOR CARRYING OUT THE INVENTION

The present inventions I and II are illustrated hereinafter.

The present invention I is comprised a hydroxyalkyl(meth)acrylatecomposition (a) modified by a small amount of lactones in which aproportion of monomers having two or more pieces (n≧2) of lactonecontinuous chains is less than 50% (area % by GPC) which is representedby formula (1), and the composition (a) is a composition obtained by amethod for the preparation in the present invention II, that is, amethod in which a hydroxyalkyl (meth)acrylate is allowed to react with alactone in a reaction molar ratio of more than 1 in the case ofpreparing the polylactone-modified hydroxyalkyl(meth)acrylate throughallowing to react the hydroxyalkyl(meth)acrylate with a lactone monomerby ring-opening polymerization. In more detail, it relates to acomposition obtained by allowing to react a lactone with a hydroxyalkyl(meth)acrylate in an atmosphere containing oxygen under the presence ofless than 1000 ppm of a catalyst and less than 1% of an inhibitor forpreventing polymerization of the hydroxyalkyl(meth)acrylate at atemperature of approximately 80-140° C.

In obtaining the composition (a) of the present invention, a reaction isconducted by feeding lactones at a feeding molar ratio of less than 1mol with respect to the hydroxyalkyl(meth)acrylate such ashydroxyethylacrylate (HEA) and hydroxyethylmethacrylate (HEMA) in orderto decrease lactone continuous chains. The catalyst to be employed inthe present invention is a variety of organic and inorganic metalcompounds, and preferred catalysts are a tin-based compound such asstannous chloride, monobutyltin tris-2-ethylhexanate, stannous octoate,and dibutyltin dilaurate. By the catalysts, there can be prepared thecaprolactone-modified hydroxyalkyl(meth)acrylate composition in whichthe lactone continuous chains are decreased. In addition to decreasingthe lactone continuous chains, although unreacted HEA and HEMA, etc. areremained, since the HEA and HEMA, etc. are often employed alone, ifthose are not more than 50% by weight, those can be often approved eventhough a mixed monomer.

Heretofore, in the case that ε-caprolactone is ring-opening polymerizedon a compound having hydroxyl groups, although the ring-openingpolymerization is conducted by adding a titanium-based catalyst such astetrabutyl titanate, tetraethyl titanate, and tetrapropyl titanate at130-230° C., even though intending to add ε-caprolactone to a(meth)acrylate having hydroxyl group at temperature conditions of notless than 130° C., the (meth)acrylate itself causes a thermalpolymerization, resulting in that it is difficult to obtain a desiredproduct.

In a temperature lower than 130° C., although there can be prevent thethermal polymerization of the (meth)acrylate itself, a ring-openingreaction rate of ε-caprolactone becomes very slow.

Since the titanium-based catalyst is relatively strong in catalyticactivity, a desired product can be obtained. However, since the catalysthas a strong activity also as a catalyst for transesterification, atransesterification reaction proceeds during the ring-openingpolymerization, resulting in that a polyvalent alcohol is removed from 2mol of the hydroxyalkyl(meth)acrylate, and an alkyleneglycoldi(meth)acrylate is by-produced.

Since such the di(meth)acrylate has a high boiling point, it isdifficult to be separated from a desired product. Moreover, if thedesired product containing such a by-product is radically copolymerizedin other (meth)acrylates and solvents, three dimensional crosslinking iscaused in a resin, and viscosity is remarkably increased or it ends tocause gelation. For that reason, there is desired the use of a catalysthaving a strong activity which allows to sufficiently proceed thereaction at a low temperature such as 80-130° C. and in a small amountand, moreover, during which the di(meth)acrylate is not produced so muchby the transesterification reaction.

As the catalyst to be employed in the present invention, there can beenumerated a stannous chloride, monobutyltin tris-2-ethyl hexanate,stannous octoate, and dibutyltin dilaurate, etc. Of those, since therecan more decrease discoloration and the transesterification reaction bythe use of monobutyltin tris-2-ethylhexanate, concentration of thecatalyst can be elevated, and it is also very excellent in view ofreduction of reaction time of period.

Addition amount of the catalyst is 1-1000 ppm, and preferably(hereinafter, in this specification, “unpreferably” means “undesirably”or “unfavorably”) 10-500 ppm.

As the hydroxyalkyl(meth)acrylate to be employed in the presentinvention, there are enumerated 2-hydroxyethyl methacrylate,2-hydroxyethylacrylate, hydroxypropylmethacrylate,hydroxypropylacrylate, 1,4-butyleneglycol monomethacrylate, and1,4-butyleneglycol monoacrylate, etc.

In the case that 1 mol of a lactone is allowed to react with 1 mol ofthe hydroxyalkyl(meth)acrylate, a reaction product is obtained as amixture of compounds represented by a formula described below (I-2)because a ring-opening reaction rate of the lactone to hydroxyl group inthe hydroxyalkyl(meth)acrylate nearly equals to a ring-opening reactionrate of the lactone to hydroxyl groups at terminals in a caprolactonewhich is a product.

(in the formula, R, R¹, R², and R³ are independently a hydrogen atom ora methyl group, “j” is an integer of 2-6, xn pieces of R⁴ and R⁵ areindependently a hydrogen atom or an alkyl group having a carbon numberof 1-12, “x” is 4-7, “n” is 0 or an integer of not less than 1, and anaverage value of “n” in the composition is not less than 0.3 to lessthan 1.0)

In the above-described reaction composition, there statisticallydistributes an unreacted product having n=0 and polycaprolactones havingn=1, 2, 3, 4, 5, . . . . Herein, it is preferred that n is not more than2, and an average value of “n” in the reaction composition is not lessthan 0.3 to less than 1.0, preferably 0.35 to less than 1.0 and,particularly, preferably 0.5 to 0.75.

In the case that the average value of “n” is less than 0.3, adhesion tovarious materials becomes unpreferably insufficient and, in the case ofnot less than 1, tackiness becomes too unpreferably strong.

In the case that the mol number of the lactone is not less than 1 mol,there are prepared products having two or more lactone continuous chainsand the purpose of the present invention cannot be unpreferablyattained. However, since the products cannot be separately refined in anindustrial fashion, the amount of lactone to be fed is decreased to lessthan 1 with respect to 1 mol of the hydroxyalkyl(meth)acrylate in orderto decrease the amount of the products having two or more lactonecontinuous chains. The lactone is allowed to react in not less than 0.3mol to less than 1.0 mol, preferably not less than 0.35 mol to less than1.0 mol, and more preferably not less than 0.5 mol to less than 0.75 molwith respect to 1 mol of the hydroxyalkyl(meth)acrylate. In the case ofa large amount of the lactone in the reaction, there are produced alarge amount of products having long chains of the lactone and,resulting in that the average value of “n” becomes too large andalthough a reaction curability and flexibility are improved in the useas raw materials for a coating, there lower hardness and acid resistancein a cured article. Contrarily, it is less than 0.3, the average valueof “n” becomes too small and abrasion resistance becomes unpreferablytoo worse.

Further, as the lactone, there can be employed ε-caprolactone,trimethylcaprolactone, δ-valerolactone, γ-butyrolactone, and a mixturethereof.

Reaction temperature is 80-150° C., and preferably 100-140° C.

In the case of lower than 80° C., reaction rate is slow and, in the caseof higher than 150° C., there is caused a thermal polymerization of a(meth)acrylate during the reaction, and gelation is possibly caused. Ina reaction system, a polymerization inhibitor is preferably added. Asthe polymerization inhibitor, there are employed hydroquinone,hydroquinone monomethylether, and phenothiazine, etc. in a range of0.01-1%, and preferably 0.03-0.5%.

In the reaction system, if an inert gas such as nitrogen is streamed,since a radical polymerization is apt to be caused, it is useful thatany gases are not streamed or air is streamed in order to prevent theradical polymerization.

In the hydroxyalkyl(meth)acrylate composition modified by a small amountof lactones prepared by a method in the present invention, the contentof residual lactones is 0-10% by weight, the content of the residualhydroxyalkyl(meth)acrylate is not less than 20 and not more than 50% byweight at most, the content of the di(meth)acrylate which is aby-product is 2% or less by weight, the content of the by-products by aMichaels addition, a (meth)acrylic polymerization, atransesterification, or other side reactions is not more than 10% byweight, the content of the catalyst is less than 1000 ppm, and thecontent of the polymerization inhibitor is not more than 1% by weight.

The lactone-modified acrylate composition having hydroxyl group of thepresent invention can provide an acrylic polyol of the present inventionhaving rich flexibility which is excellent in reactivity with acrosslinking agent by allowing to polymerize alone or copolymerize withother radically-polymerizable monomers.

Further, the acrylic polyol resin of the present invention is useful asa raw resin for a flexible polyfunctional (meth)acrylate resin coatingwhich includes urethane bonds by allowing to react the acrylic polyolresin of the present invention with polyisocyanates. The acrylic polyolresin of the present invention, as described hereinabove, can beutilized as a raw material for, in addition to the coating, aphoto-curable resin, a reactive diluent for the photo-curable resin, aflexibility modifier for an AS and an ABS resin, an acrylic resin, atackifier, an adhesive, a flexible lens for a glass, an acrylic emulsion(particularly, a reaction type one), a reactive diluent havingflexibility instead of styrene in an unsaturated polyester resin, andalso materials for a polymerizable polyurethane elastomer, etc.

As the other radically-polymerizable monomers for copolymerizing withthe lactone-modified acrylate or methacrylate composition havinghydroxyl groups of the present invention, there are enumerated anunsaturated monomer having an isocyanate group, a polymerizable monomerhaving an active hydrogen, and other polymerizable unsaturated monomers.

The other polymerizable unsaturated monomers are exemplified below.

As (meth)acrylates, for example, there are enumerated an alkyl orcycloalkyl ester having a carbon number of 1-20 of a (meth)acrylic acidsuch as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate,lauryl (meth)acrylate, cyclohexyl(meth)acrylate, isobonyl(meth)acrylate,and adamantyl(meth)acrylate; an alkoxyalkyl ester having a carbon numberof 2-8 of a (meth)acrylic acid such as methoxybutyl (meth)acrylate,methoxyethyl (meth)acrylate, and ethoxybutyl(meth)acrylate.

As other monomers except the (meth)acrylates, glycidyl(meth)acrylate;styrene, α-methylstyrene, vinyltoluene, (meth)acrylonitrile,(meth)acrolein, butadiene, isoprene, (meth)acrylic acid, etc., and thesecan be employed in mixing.

As the polymerizable monomer having an active hydrogen, there areenumerated a vinyl monomer having hydroxyl group and a vinyl monomerhaving amino group, these can be employed in mixing.

As the (meth)acrylate having hydroxyl group, for example, there areenumerated a hydroxyalkyl ester of a (meth)acrylic acid having a carbonnumber of 2-8 such as 2-hydroxylethyl(meth)acrylate and2-hydroxypropyl(meth)acrylate, 2-hydroxylethyl vinylether,N-methylol(meth)acrylic amide, Alonix 5700 manufactured by Toa GoseiKagaku Kogyo, Ltd., 4-hydroxystyrene, HE-10, HE-20, HP-10, and HP-20(all of those are an acrylate oligomer having hydroxyl group at aterminal) which are manufactured by Nihon Shokubai Kagaku Kogyo, Ltd.,Blemmer PP series (a polypropyleneglycol methacrylate), Blemmer PEseries (a polyethyleneglycol monomethacrylate), Blemmer PEP series (apolyethyleneglycol-polypropyleneglycol methacrylate), Blemmer AP-400 (apolypropyleneglycol monoacrylate), Blemmer AE-350 (a polyethyleneglycolmonoacrylate), Blemmer NKH-5050 (a polypropyleneglycol polytrimethylenemonoacrylate), and Blemmer GLM (glycerol monoacrylate) which aremanufactured by Nihon Yushi, Ltd., and an ε-caprolactone-modifiedhydroxyalkylvinyl monomer which is obtained by a reaction of a vinylcompound having hydroxyl group with ε-caprolactone, etc.

As typical examples of the ε-caprolactone-modified hydroxyalkylvinylmonomer, there are enumerated Placcel FA-1, Placcel FA-4, Placcel FM-1,and Placcel FM-4, etc. which are manufactured by Daicel Kagaku Kogyo,Ltd., TONE M-100 and TONE M201 which are manufactured by UCC, Ltd.,etc., and an average polymerization degree “n” is not less than 1.

As typical examples of the vinyl monomer having amino group, there areenumerated a variety of dialkylaminoalkyl(meth)acrylates such asdimethylaminoethyl(meth)acrylate, diethylaminoethyl (meth)acrylate,diethylaminopropyl(meth)acrylate, and dimethylaminopropyl(meth)acrylate;N-dialkylaminoalkyl(meth)acrylic amides such as N-dimethylaminoethyl(meth)acrylic amide, N-diethylaminoethyl(meth)acrylic amide,N-dimethylaminopropyl(meth)acrylic amide, andN-diethylaminopropyl(meth)acrylic amide;t-butylaminoethyl(meth)acrylate, t-butylaminopropyl(meth)acrylate,azilidinylethyl(meth)acrylate pyrolidinylethyl(meth)acrylate,piperidinylethyl(meth)acrylate, vinylpiridine, and aminoethylvinylether,etc. and, the dialkylaminoalkyl(meth)acrylates andN-dialkylaminoalkyl(meth)acrylic amides are particularly preferred froma viewpoint of curability, etc.

As the monomer having isocyanate group, for example, there areenumerated isocyanate ethyl(meth)acrylate, isocyanatepropyl(meth)acrylate, isocyanate butyl(meth)acrylate, isocyanatehexyl(meth)acrylate, m-isopropenyl-α,α′-dimethylbenzyl isocyanate, andm-ethylenyl-α,α′-dimethylbenzyl isocyanate, etc., and an unsaturatedcompound obtained by addition of a polyisocyanate such as hexamethylenediisocyanate compound to the above-described polymerizable monomerhaving an active hydrogen such as the hydroxyethyl(meth)acrylate, andthese can be employed in mixing.

The above-described radically-polymerizable monomers can be alsoemployed in mixing and, those are selectively employed according todesired physical properties.

The acrylic polyol resin of the present invention is prepared byradically-polymerizing the polylactone-modified hydroxyalkylacrylate ormethacrylate of the present invention and the above-describedradically-polymerizable monomers under the presence of a radicalpolymerization initiator by publicly-known solution polymerizationmethods.

As the radical polymerization initiator, there can be employed aperoxide initiator such as benzoyl peroxide, t-butylhydroperoxide,cumylhydroperoxide, cumenhydroperoxide, t-butyl peroxybenzoate, andt-butylperoxy-2-ethylhexanoate, and an azo-based initiator such asazobisisobutyronitrile and azobisdimethylvaleronitrile.

As solvents for polymerization to be employed in the solutionpolymerization, if those are a nonreactive solvent, there can beemployed hydrocarbons (benzene, toluene, xylene, n-hexane, andcyclohexane, etc.), acetates (ethyl acetate, propyl acetate, and butylacetate, etc.), alcohols (methanol, ethanol, isopropanol, and n-butanol,etc.), ethers (ethyl cellosolve, butyl cellosolve, and cellosolveacetate, etc.), ketones (methylethylketone, acetoethyl acetate,acetylacetone, diacetone alcohol, methyl isobutyl ketone, and acetone,etc.) without any limitation. The solvents may be employed solely or incombination of two or more kinds.

As a reaction vessel to be employed for the above-describedpolymerization, there are preferably employed a reaction vessel equippedwith an agitation and a reflux condenser equipped with a drying tube anda twin-screw extruder.

Polymerization temperature and polymerization time of period depend uponrespective kinds and feeding ratio of the polylactone-modifiedhydroxyalkyl acrylate or methacrylate composition of the presentinvention and the above-described radically-polymerizable monomer, kindand amount of the catalyst and, further, reaction vessels, and those arenot particularly limited, and those are appropriately decided by the useof a desired acrylic resin, for example, physical properties of acoating layer to be required in the case of a coating.

Hereinafter, the present invention III is illustrated.

The present invention III is a curable resin composition containing anacrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylatecomposition (a) modified by a small amount of lactones in which aproportion of monomers having not less than 2 continuous chains (n≧2) oflactones is less than 50% (GPC area %), which is represented by theabove-described general formula (I) as polymerizing components, and amelamine resin (B).

The hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactones is as illustrated in the present invention I.

The acrylic polyol resin (A) to be employed in the present invention iscomprised 5-70 parts by weight of the hydroxyalkyl (meth)acrylatecomposition (a) modified by a small amount of lactones, 0-90 parts byweight of an alkyl(meth)acrylate having an alkyl group of a carbonnumber of 1-20, 0-30 parts by weight of a (meth)acrylic acid, and 0-40parts by weight of other polymerizable unsaturated monomer. As the otherpolymerizable unsaturated monomer, there are enumeratedradically-polymerizable monomers other than the alkyl(meth)acrylate asexemplified in the present invention I. Conditions for the preparationthereof are as illustrated in the present invention I.

In the acrylic polyol resin (A), hydroxyl value is 5-250, and a numberaverage molecular weight is 3,000-300,000.

As the melamine resin (B) to be employed in the present invention, therecan be employed a usual melamine resin for coating without anymodification, and an imino type or methylol type melamine resin isemployed. Since an isocyanate compound is not employed as a curingagent, it is excellent in handling and safeness. The imino type ormethylol type melamine resin is not particularly limited, and as a resincapable of reacting with hydroxyl group, if it is a melamine to beemployed for a coating system in which hydroxyl group is employed as afunctional group, it is not particularly limited. As such the imino typemelamine resin, for example, there are enumerated Yuban 22R (solidcontent of 60%), Yuban 21R (solid content of 50%), and Yuban 2028 (solidcontent of 75%) (all of those are an imino type melamine resin), etc.which are manufactured by Mitsui Kagaku. On the other hand, as themethylol-type melamine resin, there can be employed a melamine resinhaving a condensation degree of 1.1-20 or so which is prepared bymelamine, formaldehyde, a monoalcohol having a carbon number of 1-4, andoptionally, water which are raw materials. For example, there areenumerated Yuban 60R (solid content of 50%) manufactured by MitsuiKagaku and Superbekkamine L-121-60 (solid content of 60%) manufacturedby Dainippon Ink Kagaku Kogyo, Ltd.

The curable resin composition of the present invention contains 0.5-80parts by weight of the acrylic polyol resin (A) obtained using thecomposition (a) and 0.5-50 parts by weight of the melamine resin (B).Total of the (A) and the (B) does not exceed 100 parts by weight.

In the case that the acrylic polyol resin (A) is less than 0.5 part byweight, bending resistance becomes insufficient and, in the case ofexceeding 80 parts by weight, abrasion resistance unpreferably lowers.In the case that the melamine resin (B) is less than 0.5 part by weight,solvent resistance is not sufficient and, in the case of exceeding 50parts by weight, acid resistance becomes unpreferably insufficient.

By another representation of the use ratio of the acrylic polyol resin(A) with respect to the melamine resin (B), 60-10% by weight of themelamine resin (B) is employed together with 40-90% by weight of theacrylic polyol resin (A). In the case that the use ratio of the acrylicpolyol resin (A) is less than 40% by weight, a self condensationreaction of the melamine resin (B) itself increases, resulting in that acoating layer becomes brittle and, for example, it does not becomeappropriate as a coating for a molded article of a polyolefine-basedresin. On the other hand, in the case that the use ratio of the acrylicpolyol resin (A) exceeds 90% by weight, crosslinking becomesinsufficient, and solvent resistance and weatherability lower. Apreferred use ratio of the acrylic polyol resin (A) is 60-80% by weight,and the use ratio of the melamine resin (B) is 40-20% by weight.

In the the acrylic polyol resin (A), the melamine resin (B), and theacidic catalyst for curing which is optionally employed in the presentinvention, total acid value is 5-50, and preferably 15-35. In the casethat the total acid value is less than 5, crosslinkable reactivitylowers and crosslinking becomes insufficient, and there lower gasolineresistance and weatherability. On the other hand, in the case that thetotal acid value exceeds 50, storage stability lowers, and waterresistance lowers. As described above, by controlling the acid value, acoating composition can be modified to low temperature curability.

In order to give an acid value to the acrylic polyol resin (A), amonomer having carboxylic group and a phosphoric acid group is employedtogether as the polymerizable vinyl monomer to introduce the acid groupsinto the acrylic polyol resin (A). Further, adjustment of the acid valuecan be conducted by formulating the acidic catalyst for curing into acoating composition. As such the acidic catalyst for curing, a weakacidic catalyst for curing is employed. As such the weak acidic catalystfor curing, for example, there are enumerated phosphoric acids, amonophosphate, a monophosphite, a phosphate containing an unsaturatedgroup, and carboxylic acids, etc. As such the weak acidic catalyst forcuring, phosphoric acids and phosphates thereof are particularlypreferred. As such the phosphoric acids and phosphates thereof, forexample, there are enumerated a phosphoric acid, a pyrophosphoric acid,and a mono or diphosphate, etc. As the monophosphate, for example, thereare enumerated monooctyl phosphate, monopropyl phosphate, and monolaurylphosphate, etc. As the diphosphate, for example, there are enumerateddioctyl phosphate, dipropyl phosphate, and diraulyl phosphate, etc.Further, mono(2-(meth)acryloyloxyethyl)acid phosphate is enumerated.Still further, there may be even employed a compound obtained byallowing to react a compound having an acid anhydride group with apolyol or an alcohol. Besides, an oligomer having an acid value may bealso blended. In the case, as a method for introducing an acid valueinto the acrylic polyol resin (A) and other oligomers, for example,there is a method in which there is employed a polymerizable vinylmonomer having carboxylic group or a phosphoric acid group in the caseof graft-polymerizing or (co)polymerizing. It is to be noted that thecarboxylic group or the phosphoric acid group preferably exists at notless than 10 atoms-apart position from a main chain of the oligomer,whereby, it readily reacts at a low temperature.

The acidic catalyst for curing is employed in the amount of 0.001-10% byweight, and preferably 0.001-5% by weight based on total weight of theacrylic polyol resin (A) and the melamine resin (B).

The coating composition of the present invention is modified to acoating composition without any modification or by appropriatelyformulating, optionally, a variety of additives which are conventionallyemployed in a coating field, for example, coloring pigments, extenderpigments, an aluminum powder, a pearl mica powder, an anti-droppingagent or an anti-sedimentation agent, a levelling agent, a dispersant, adefoaming agent, an ultraviolet ray absorbent, a photo-stabilizer, anantistatic agent, and a thinner, etc.

As the coloring pigments, for example, there are enumerated inorganicpigments such as titanium oxide (for example, titanium oxide pigments,Taipek CR-95 (manufactured by Ciba Geigy, AG)), carbon black, ironoxide, iron red, lead molybdenum acid, chromium oxide, and leadchromate, phthalocyanine pigments such as phthalocyanine blue andphthalocyanine green, organic pigments such as quinaklidone red, azopigments, and anthraquinone pigments, etc.

As the extender pigments, for example, there can be employed kaoline,talc, silica, mica, barium sulphate, and calcium sulphate, etc. As theanti-dropping agent or an anti-sedimentation agent, for example, therecan be preferably employed bentonite, a linseed oil wax, an amide wax,micro gel (for example, MG100S (manufactured by Dainippon Ink)), and analuminum acetate, etc.

As the levelling agent, for example, there can be preferably employed asilicone-based surface active agent such as KF69, Kp321, and Kp301(hereinabove, manufactured by Shin-etsu Kagaku), Modaflow (a surfacecontrolling agent manufactured by Mitsubishi Monsant), BYK301, and 358(manufactured by Bickchemie Japan), and Diaaide AD9001 (manufactured byMitsubishi Rayon), etc.

As the dispersant, for example, there can be preferably employedAnti-Terra U or Anti-Terra P and Disperbyk-101 (hereinabove,manufactured by Bickchemie Japan), etc.

As the defoaming agent, for example, there can be preferably employedBYK-0 (manufactured by Bickchemie Japan), etc.

As the ultraviolet ray absorbent, for example, there can be preferablyemployed a benzotriazole-based ultraviolet ray absorbent such as Tinuvin900, Tinuvin 384, and Tinuvin P (hereinabove, manufactured by CibaGeigy), an anilide oxalate-based ultraviolet ray absorbent such asSandbar 3206 (manufactured by Sand), etc.

As the photo-stabilizer, for example, there can be preferably employed ahindered amine-based photo-stabilizer such as Sanol LS292 (manufacturedby Sankyo) and Sandbar 3058 (manufactured by Sand), etc.

As the thinner, for example, there can be preferably employed anaromatic compound such as toluene, xylene, and ethylbenzene, alcoholssuch as methanol, ethanol, propanol, butanol, and isobutanol, ketonessuch as acetone, methylisobutyl ketone, methylamyl ketone,cyclohexanone, isophorone, and N-methylpyrrolidone, ester compounds suchas ethyl acetate, butyl acetate, and methylcellosolve, or a mixturethereof, etc. As the antistatic agent, for example, there can bepreferably employed Esocard C25 (manufactured by Lion Armer), etc. Inthe case of preparing the coating composition of the present invention,there are mixed the acrylic polyol resin (A), the melamine resin (B),and optionally, additives such as acidic catalysts and pigments, anduniformly dispersed by a dispersing machine such as a sandgrind mill, aball mill, and an atlighter to prepare (a curable coating composition)of the present invention.

As a method for coating the curable coating composition (a coatingcomposition) of the present invention, an article to be coated is coatedusing a publicly-known dewaxing cleaning apparatus, for example, afterdewaxing by an organic solvent such as 1,1,1-trichloroethane, cleaningby an alkali, cleaning by an acid, wiping by a solvent, etc., further,optionally, in order to further elevate an adhesive power of a coatingto the article to be coated, for example, the coating composition of thepresent invention is directly coated by an air-spraying coating methodand an airless coating method after coating a primer such as Primac NO.1500 (manufactured by Nihon Yushi), and optionally, it is set for0.5-120 minutes, and preferably 1-20 minutes, and thermally cured(baked) at a low temperature of 90-140° C., and preferably 100-120° C.

A clear coating may be coated onto a base coat coating which is an underlayer by a wet-on-wet method. In the present invention, since curing canbe conducted at a low temperature of not more than 140° C. by theabove-described construction, it does not give a damage even on apolyolefine-based resin molded article, and there can be formed acoating layer having excellent properties of a coating layer.

In the case that a primer is coated, layer thickness after drying isgenerally 3-20 μm, and preferably 5-15 μm. Further, layer thicknessafter drying of the clear coat coating is generally 15-45 μm, andpreferably 20-35 μm. As a method for the coating composition of thepresent invention, there are enumerated a 2-coat/1-baking type coatingmethod and 3-coat/2-baking type coating method, etc.

Herein, the 2-coat/1-baking type is one of coating methods by an overcoating and, first of all, there is coated a base coat coating in whichpigments and/or metal powder are formulated in a large amount and, thereis coated a transparent clear coating or a top coating which is a colorclear coating containing a small amount of pigments, and those coatingsare simultaneously baked.

In the case of the 2-coat/1-baking type coating method, as a base coat,a usual coating composition is employed and, the coating composition ofthe present invention can be employed as a top coat.

In the case of the 3-coat/2-baking type coating method, there is coatedand baked a coating in which there are formulated pigments, dyes, andmetal powder and, there is further coated thereon and baked a base coatin which there are formulated pigments, dyes and/or metal powder, andthen, there is coated thereon and collectively baked a transparent clearcoating or a top coat which is a color clear coating containing a smallamount of pigments or dyes.

IV

Hereinafter, the present invention IV is illustrated.

The melamine curable type water-based coating composition of the presentinvention IV is comprised 5-60 parts by weight of an acrylic polyolresin (A) and 10-60 parts by weight of an amino-plasto resin (IV-B), andpreferably, 10-50 parts by weight of an acrylic polyol resin (A) and20-40 parts by weight of an amino-plasto resin (IV-B). The acrylicpolyol resin (A) to be employed in the present invention can provide anacrylic polyol resin (A) which is excellent in a reactivity with acrosslinking agent and rich in flexibility by allowing to polymerizealone the hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactones represented by the above-described general formula(1) or to copolymerize with other radically-polymerizable monomers, andit can be employed as a material for the melamine curable typewater-based coating composition of the present invention.

As other radically-polymerizable monomers for copolymerizing with thehydroxyalkyl(meth)acrylate composition

(a) modified by a small amount of lactones in the present invention,there can be employed at least one or more kinds selected from the groupconsisting of (b)-(i) described below.

(b) a polymerizable monomer containing an active hydrogen.

(c) an N-alkoxymethyl(meth)acrylic amide having an alkyl group of acarbon number of 1-6.

(d) an alkyl(meth)acrylate having an alkyl group of a carbon number of1-20.

(e) an aliphatic or cycloaliphatic vinyl monomer having a carbon numberof 2-12.

(f) an aromatic vinyl monomer.

(g) an adduct of a glycidyl ester of a (meth)acrylic acid with a fattyacid having a carbon number of 8-20.

(h) an adduct of a (meth)acrylic acid with an monoepoxy compound havinga carbon number of 8-20.

(i) an unsaturated monomer containing an isocyanate group.

As the polymerizable monomer containing an active hydrogen (b), thereare enumerated a (meth)acrylate having hydroxyl group, a (meth)acrylatehaving amino group, and α,β-ethylenic unsaturated carboxylic acid (b),etc., which are described hereinafter.

As the (meth)acrylate having hydroxyl group, for example, there areenumerated hydroxyalkyl(meth)acrylates having a carbon number of 2-8such as hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, and4-hydroxybutyl(meth)acrylate, and those can be employed in mixing.

As the (meth)acrylate having amino group, for example, there areenumerated amino alkyl esters such as dimethylaminoethyl (meth)acrylate,diethylaminoethyl(meth)acrylate, (meth)acrylic amide, andN-isopropylmethyl(meth)acrylic amide, etc.

Further, N,N-dimethylaminoethyl(meth)acrylate and dimethyl(meth)acrylicamide, etc. are employed together.

As the α,β-ethylenic unsaturated carboxylic acid, there are enumeratedethylenic unsaturated carboxylic acids such as acrylic acid, methacrylicacid, crotonic acid, maleic acid (anhydride), itaconic acid (anhydride),and fumaric acid.

As the N-alkoxymethyl (meth)acrylic amide (c) having an alkyl group of acarbon number of 1-6, there are enumerated N-methoxy(meth)acrylic amide,N-ethoxymethyl(meth)acrylic amide, N-butoxymethyl(meth)acrylic amide,etc., and N-methoxymethyl acrylic amide is preferred. Further, useamount thereof is 1-25% by weight in a water-based acrylic resin. In thecase of less than 1% by weight, water resistance of a coating layerbecomes insufficient because of lack of curability and, in the case ofnot less than 25% by weight, adhesion and processability are poor, andan aesthetic market value lowered because of a remarkable discolorationin a coating layer.

As the alkyl(meth)acrylate (d) having an alkyl group of a carbon numberof 1-20, for example, there are enumerated an alkyl orcycloalkyl(meth)acrylate having a carbon number of 1-20, such asmethyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate,lauryl(meth)acrylate, cyclohexyl(meth)acrylate, isobonyl(meth)acrylate,and adamantyl(meth)acrylate. As alkoxyalkylester (d′) having an alkylgroup of a carbon number of 2-8, there are enumerated methoxybutyl(meth)acrylate, methoxyethyl(meth)acrylate, and ethoxybutyl(meth)acrylate.

As the aliphatic or cycloaliphatic vinyl monomer (e) having a carbonnumber of 2-12, there are enumerated (meth)acrylonitrile and(meth)acrolein; butadiene and isoprene; vinyl esters or isopropenylesters such as vinylacetate, vinylpropionate and isopropenyl acetate;vinylethers such as ethyl vinylether, butyl vinylether, cyclohexylvinylether, and phenylvinyl ether.

As the aromatic vinyl monomer (f), there are enumerated styrene,α-methylstyrene, and vinyl toluene, etc.

As the glycidyl ester (g) of a (meth)acrylic acid, for example, there isenumerated a glycidyl(meth)acrylate, etc.

As the adduct (g′) of a glycidyl ester of a (meth)acrylic acid with afatty acid having a carbon number of 8-20, there is enumerated an adductof a glycidyl(meth)acrylate with a fatty acid having a carbon number of8-20 such as oleic acid, lauric acid, and stearic acid.

As the adduct (h) of a (meth)acrylic acid with an monoepoxy compoundhaving a carbon number of 8-20, there is enumerated an adduct of a(meth)acrylic acid with Kardula E10 (a glycidyl ester of a branchedhigher fatty acid manufactured by Shell Chemicals, Ltd.).

As the monomer (i) containing an isocyanate group, for example, thereare enumerated isocyanate ethyl(meth)acrylate, isocyanatepropyl(meth)acrylate, isocyanate butyl(meth)acrylate, isocyanatehexyl(meth)acrylate, m-isopropenyl-α,α′-dimethylbenzyl isocyanate, andm-ethylenyl-α,α′-dimethylbenzyl isocyanate, etc., and further, anunsaturated compound in which a polyisocyanate compound such ashexamenthylene diisocyanate is added to the above-describedpolymerizable monomer containing an active hydrogen such ashydroxyethyl(meth)acrylate and, those can be employed in mixing.

The above components (b)-(i) can be employed by mixing of one or morekind in or between respective components.

In the acrylic polyol resin (A), for example, there can be preferablyemployed 3-40% by weight of the hydroxyalkyl(meth)acrylate composition(a) modified by a small amount of lactones, 1-20% by weight of theα,β-unsaturated carboxylic acid, 1-25% by weight of theN-alkoxymethyl(meth)acrylate having an alkyl group of a carbon number of1-6, and the aromatic vinyl monomer and the alkyl(meth)acrylate in theresidual amount which is that 100% by weight minus total amount of theabove.

In the acrylic polyol resin (A), for example, preferably, a numberaverage molecular weight is 2,000-50,000, a hydroxyl value is 10-150mg-KOH/g, and Tg point is 0-60° C.

The acrylic polyol resin (A) to be employed in the present invention isas illustrated in the present invention I.

Amino-plasto resin (IV-B)

Melamine resin (j) is at least one kind of a guanamine resin (k)selected from the group consisting of benzoguanamine, spyroguanamine,acetoguanamine, and phthaloguanamine; and/or a melamine-guanaminecocondensation resin (I), and it is partially etherized by a monovalentalcohol having a functional group of a carbon number of 1-6.

As the alcohol, for example, there is employed an alkyl alcohol having acarbon number of 1-4 such as methanol, ethanol, n-propanol, isopropanol,n-butanol, and isobutanol, etc., alone or in mixing.

Specifically, there are enumerated a methyletherized methylol melamineresin, a methyletherized methylol benzoguanamine resin, amethyletherized melamine-benzoguanamine cocondensation resin, abutyletherized methylol melamine resin, a butyletherized methylolbenzoguanamine resin, and a methoxy-ethoxy mixed etherizedbenzoguanamine resin, etc. Of those, there are particularly preferredthe methyletherized, and methoxy-ethoxy mixed etherized ormethoxy-ethoxy mixed etherized melamine-benzoguanamine copolymerizedresin from a viewpoint of retort resistance and processability.

The melamine curable type water-based coating composition of the presentinvention is comprised 5-60 parts by weight of an acrylic polyol resin(A) and 10-60 parts by weight of an amino-plasto resin (IV-B), andpreferably, 10-50 parts by weight of an acrylic polyol resin (A) and20-40 parts by weight of an amino-plasto resin (IV-B). In the case thatthe acrylic polyol resin (A) is less than 5 parts by weight, hardness ofa coating layer remarkably lowers and, in the case of exceeding 60 partsby weight, retort resistance is unpreferably deteriorated. In the casethat the amino-plasto resin (IV-B) is less than 10 parts by weight,curability lowers and, in the case of exceeding 60 parts by weight,processability unpreferably lowers.

The alkyletherized melamine resins are employed in an amount of 5-40% byweight in an over coat coating. In the case that the amount of thealkyletherized melamine resins is less than 5% by weight, acrossslinking reaction does not sufficiently proceed, and there lowersolvent resistance and acid rain resistance. Further, in the case ofexceeding 40% by weight, flexibility lowers in a coating layer, andthere lowers bending resistance and impact resistance. In the case thatthe alkyletherized melamine resins alone are employed as a crosslinkingagent, the alkyletherized melamine resins are employed in an amount of20-40% by weight in an over coat coating. In the case of being less than20% by weight, a crosslinking reaction does not sufficiently proceed,and there lower solvent resistance and acid rain resistance.

It is to be noted that it is preferred to optionally employ together ablocked polyisocyanate compound as a crosslinking agent.

By the use thereof, use amount of the alkyletherized melamine resins canbe reduced and, a staining resistance is further improved owing to arelative decrease of an ether bond. Use amount thereof is 20% by weightat most, and in the case that it is formulated in exceeding 20% byweight, there lowers curability at a low temperature unpreferably.

As the blocked polyisocyanate compound, there are exemplified apolyhexamethylene diisocyanate which is an active methylene compoundisocyanurate type and a polytetramethyl xylilene diisocyanate which is amethylethylketoxime blocked adduct type.

In the melamine-curable water-based coating composition of the presentinvention, there can be optionally employed an acidic catalyst, oramine-block agent thereof, for example, p-toluene sulphonic acid,dodecylbenzene sulphonic acid, dinonylnaphthalene sulphonic acid, and anamine blocking agent thereof in an amount of 0.1-4.0 parts by weightbased on 100 parts by weight of solid content of resins as a curingcatalyst. Likewise, there can be also added a defoaming agent, aleveling agent, and a lubricant, etc.

Further, there can be added pigments such as titanium oxide, an aluminumpigment, and quinaklidone by dispersing and kneading in theabove-described water-based acrylic resin or a mixture of thewater-based acrylic resin with other water-based resin using apublicly-known dispersing machine such as a sandmill or disper toprepare a pigment paste, followed by preparing a coating using the samemethod described hereinabove.

Still further, the melamine curable type water-based coating compositioncan be mixed with a water-soluble resin and a water-dispersible resin,for example, a resin such as a polyester, a polyetherpolyol, apolyesterpolyol, a polyurethanepolyol, a maleic-modified fatty acid, andan adduct of ethyleneoxide or propyleneoxide to bisphenol A, which areusually employed.

Furthermore, in the melamine curable type water-based coatingcomposition, there can be also mixed an acrylic resin having a glasstransition temperature of exceeding 0° C. or an acrylic resin having aglass transition temperature of not more than 0° C. according to usesthereof.

The melamine curable type water-based coating composition can be coatedon a substrate by publicly-known means such as a roll coating, spraycoating, and brush coating, etc.

A metallic base plate includes an extended steel plate, a stainlesssteel plate, and an aluminum alloy plate which have a plate thickness of0.01-2.0 mm. In the metallic plates, surface is treated by at least oneor more kinds of alloy or a composite which include an inorganic metalsuch as chromium, tin, zinc, and nickel an organic material such as anacrylic resin, using such as methods as plating, vapor deposition,coating, zirconium, alumite, and phosphate, etc. Further, there can beemployed a metal plate in which a resin film such as a polyethyleneterephthalate or a polybutylene terephthalate is laminated with theplates.

Hereinafter, the present invention IV is illustrated.

The present invention IV is a curable resin composition containing anacrylic polyol resin (V-A) obtained using a hydroxyalkyl(meth)acrylatecomposition (a) modified by a small amount of lactones in which aproportion of monomers having not less than 2 continuous chains (n 2) oflactones is less than 50% (GPC area %), and which is represented by theabove-described general formula (1), and a polyisocyanate compound(V-B).

The hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactones to be employed in the present invention is asillustrated in the present invention I.

By allowing to polymerize the hydroxyalkyl(meth)acrylate compositionmodified by a small amount of lactones to be employed in the presentinvention alone or copolymerize with other radically-polymerizablemonomers, there can be provided an acrylic polyol resin having anexcellent reactivity with an crosslinking agent and rich flexibility,and it can be utilized as a material for the curable resin compositionfor a coating of the present invention.

As the other radically-polymerizable monomers to be copolymerized withthe (meth)acrylate composition having hydroxyl group modified by a smallamount of lactones to be employed in the present invention, there areenumerated a polymerizable monomer having an active hydrogen and otherpolymerizable unsaturated monomers, which include monomers exemplifiedin the present invention I.

The other radically-polymerizable monomers can be also employed inmixing, and those are selectively employed depending upon desiredphysical properties.

Preferably, the acrylic polyol resin (V-A) is comprised 5-65% by weightof the hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactones, 0-30% by weight of the vinyl monomer having hydroxylgroup, and other vinyl-based monomers of a residual amount which is that100% by weight minus total amount of the above monomers.

The acrylic polyol resin (V-A) to be employed in the present inventionis prepared according to the methods in the present invention II.

The polyisocyanate compound (V-B) to be employed in the presentinvention is an aromatic, aliphatic, and cycloaliphatic polyisocyanateand, there are preferred an aromatic polyisocyanate having a carbonnumber of 6-30, an aliphatic polyisocyanate having a carbon number of4-30, and a cycloaliphatic polyisocyanate having a carbon number of8-30. For example, there are typically enumerated 2,4-naphthalenediisocyanate, 1,5-naphthalene diisocyanate, 4,4′-diphenylmethanediisocyanate, 4,4′-diphenyldimethylmethane diisocyanate,dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethanediisocyanate, 4,4′-diphenylenemethane diisocyanate, 4,4′-dibenzyldiisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, atolylene diisocyanate such as 2,4-tolylene diisocyanate and 2,6-tolylenediisocyanate, xylilene diisocyanate such as p-xylilene diisocyanate andm-xylilene diisocyanate, 1,4-tetramethylene diisocyanate,1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate,2,2,4-trimethylhexamethylene-1,6-diisocyanate,2,4,4-trimethylhexamethylene-1,6-diisocyanate, ridine diisocyanate,cyclohexane-1,4-diisocyanate, isophorone diisocyanate,4,4′-diisocyanatedicyclohexane, 4,4′-diisocyanate dicyclohexane,dicyclohexylmethane-4,4′-diisocyanate,1,3-bis(isocyanatemethyl)cyclohexane, and methyl cyclohexanediisocyanate such as methyl cyclohexane-2,4-(or -2,6-)diisocyanate,etc., or an adduct of the diisocyanates to a polyvalent alcohol such asethylene glycol, propylene glycol, a polyethylene glycol, apolypropylene glycol, a polycaprolactone polyol, trimethylol ethane, andtrimethylol propane, a polyester resin (including an oil-modified type)having a functional group which reacts with isocyanate group, an acrylicresin, etc., and water, etc., a buret compound, a polymer allowed toreact between isocyanates, or an equal mol adduct of 2-hydroxypropyl(meth)acrylate-hexamethylene diisocyanate, a copolymer essentiallycontaining a vinyl-based monomer having a copolymerizable unsaturatedgroup with an isocyanate group such as isocyanateethyl (meth)acrylate,or compounds described in JP-A-61072013 Official Gazette, and a blockedcompound blocked by a blocking agent such as a lower monovalent alcohol,phenols, methylethylketoxime, and a lactam, etc.

The diisocyanates may be employed solely or even in combination of towor more kinds.

From a viewpoint of a color tone in a coating layer obtained using thecurable resin composition of the present invention, as a polyisocyanatecompound, nonyellowing type polyisocyanates are preferred, and thefollowing ones are disclosed as an example.

There are enumerated aliphatic-based polyisocyanates such as1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate,1,6-hexamethylene diisocyanate,2,2,4-trimethyl-1,6-hexamethylenediisocyanate, and ridine diisocyanate;cycloaliphatic-based polyisocyanates such as isophorone diisocyanate,methyl cyclohexane-2,4-(or -2,6-)diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and 1,3-bis(isocyanatemethyl) cyclohexane,and the above-described derivatives (including an adduct) therefrom. Ofthose, there are preferably enumerated 1,6-hexamethylene diisocyanate(hereinafter, abbreviated as HMDI), isophorone diisocyanate(hereinafter, abbreviated as IPDI), and a derivative (including anadduct) therefrom in view of weatherability and an ease ofindustrially-obtaining.

Since the polyisocyanate compounds react with polyols in a base materialeven at room temperatures, those include a drawback that those are poorin storage stability, and handling is troublesome and, those areunpreferred in view of safeness and hygiene. Accordingly, blocked typepolyisocyanates are preferred as the polyisocyanate compounds.

Although the blocked type polyisocyanates (hereinafter, occasionallyreferred to as a highly-branched block polyisocyanate) are obtained evenonly by allowing to react the polyisocyanates with a polyvalent alcohol,more preferably, those can be obtained by cyclic trimerization of anisocyanate, that is, isocyanuration after allowing to react adiisocyanates with the polyvalent alcohol.

As the polyvalent alcohol in the case, there is preferred an alcoholhaving three or more functionalities and, as a polyvalent alcohol havinga low molecular weight, for example, there are enumerated trimethylolpropane, glycerine, 1,1,7-trimethylol heptane, 1,2,7-trimethylolheptane, and pentaerythritol, etc. As a polyvalent alcohol having ahigher molecular weight, for example, there are enumerated aliphatichydrocarbon polyols, polyether polyols, polyester polyols, and epoxyresins, etc.

As the aliphatic hydrocarbon polyols, for example, there are enumerateda polybutadiene having hydroxyl group at terminals and a hydrogenateproduct therefrom, etc. Further, as the polyether polyols, for example,there are enumerated so-called polymer polyols, etc. obtained bypolymerizing acrylic amides in media which are polyether polyols inwhich an alkylene oxide such as ethyleneoxide or propyleneoxide is addedalone or in a mixture to polyvalent alcohols such as glycerine orpropyleneglycol, polytetramethylene glycols, or polyethers in whichpolyfunctional compounds such as ethylenediamine or ethanolamines areadded to an alkylene oxide.

As the polyester polyols, there are enumerated polyester polyol resinsobtained by condensation reaction of at least one of a polybasic acidwith at least one of polyvalent alcohols, and polycaprolactones obtainedby ring-opening polymerization of ε-caprolactone using polyvalentalcohols.

As the polybasic acid, for example, there are enumerated phthalic acid(anhydride), terephthalic acid, isophthalic acid, tetrahydrophthalicacid (anhydride), hexahydrophthalic acid (anhydride),3-methylhexahydrophthalic acid (anhydride), 4-methylhexahydrophthalicacid (anhydride), 3-methyltetrahydrophthalic acid (anhydride),trimellitic acid (anhydride), pyromellitic acid (anhydride), het acid(anhydride), hymic acid (anhydride), adipic acid, sebasic acid, azelaicacid, succinic acid (anhydride), maleic anhydride, fumaric acid,itaconic acid, and a dimer acid, etc. The acid may be employed even inthe form of an ester of a lower alcohol such as dimethylisophthalate anddimethylterephthalate.

The polyvalent alcohols are a compound having at least two alcoholic orphenolic hydroxyl groups in the molecule, for example, there arespecifically enumerated ethylene glycol, diethylene glycol,triethyleneglycol, polyethyleneglycol, 1,6-hexanediol, pentanediol,cyclohexane dimethanol, propylene glycol, butylene glycol, butylenediglycol, trimethylol ethane, trimethylol propane, glycerine, neopentylglycol, sorbitol, tris(2-hydroxyethyl)isocyanurate, diethanol amine,diisopropanol amine, bisphenol A, and bisphenol F, etc.

As the epoxy resins, for example, there are enumerated a novolak type,β-methylepichlorohydrin type, a cyclic oxirane type, a glycidylethertype, a glycolether type, an epoxy type of an aliphatic unsaturatedcompound, an epoxidized fatty acid ester type, a polycarboxylic acidester type, an aminoglycidyl type, a halogenated type, and resorcinoltype, etc.

Of the polyols, there are preferably employed the above-describedpolyvalent alcohol having a low molecular weight and a polyether polyolhaving 3-8 pieces of hydroxyl groups in the molecule, the aliphatichydrocarbon polyols, and polyester polyols and, particularly preferably,the polyester polyols. These may be employed solely or in combination oftwo or more kinds. Aliphatic or cycloaliphatic diisocyanate and thepolyvalent alcohols are allowed to react at 50-200° C., and preferably50-150° C. In the case, solvents may be even employed, and there arepreferably employed solvents which are inactive to an isocyanate. Assuch the inactive organic solvents, for example, there are employed atleast one kind of aliphatic hydrocarbons such as hexane, heptane, andoctane; aromatic hydrocarbons such as benzene, toluene, and xylene;esters; and ketones. Since the solvents occasionally contain moisture,it is preferred to optionally remove the moisture. Although the reactioncan be conducted even after an isocyanuration reaction, it is preferablyconducted prior to the isocyanuration reaction.

In the isocyanuration reaction, catalysts are usually employed. Inusual, the catalysts to be employed herein are preferably basic, forexample, there are employed a quaternary ammonium salts and a weakorganic acid salt thereof, an alkyl metal salt of an alkyl carboxylicacid, an metal alcholate, and a compound having an aminosilyl group,etc. Concentration of the catalysts is usually selected from a range of210 ppm to 1.0% based on isocyanate compounds.

In the reaction, solvents may be employed or even not employed. In thecase that the solvents are employed, there should be employed solventswhich are inert to an isocyanate group.

Reaction temperature is usually 20-160° C., and preferably 40-130° C.Termination point of the reaction depends upon the kind of thepolyvalent alcohols to be employed, and it is a period at which yieldattains to approximately 30%. When the reaction attains to a targetyield, for example, the reaction is terminated by deactivation of thecatalysts by, for example, sulphonic acid, phosphoric acid, andphosphates, etc.

In a highly-branched polyisocyanate having an isocyanurate structureafter removal of unreacted diisocyanates and solvents, viscosity at 25°C. is preferably 0.5 to 300 Pas. In the case that the viscosity exceeds300 Pas, outer appearance in a coating layer is adversely affectedoccasionally and, in the case of being less than 0.5 Pas, it isdifficult to obtain a range of an average functional group number of thepolyisocyanate regulated in the present invention.

As a blocking agent for obtaining the highly-branched blockpolyisocyanate, for example, there are enumerated phenol-based ones suchas phenol, cresol, xylenol, ethylphenol, o-isopropylphenol, butylphenolsuch as p-tert-butylphenol, p-tert-octylphenol, nonylphenol,dinonylphenol, styrenized phenol, oxybenzoic acid phenol, thymol,p-naphthol, p-nitrophenol, p-chlorophenol; alcohol-based ones such asmethanol, ethanol, propanol, butanol, ethyleneglycol, methylcellosolve,butylcellosolve, methylcarbitol, benzyl alcohol, phenylcellosolve,fulfurylalcohol, and cyclohexanol; active methylene-based ones such asdimethyl maloate, diethyl maloate, methylacetoacetate,ethylacetoacetate, and acetyl acetone; mercaptan-based ones such asbutyl mercaptan, thiophenol, and tert-dodecyl mercaptan; amine-basedones such as diphenyl amine, phenylnaphtyl amine, aniline, andcarbazole; acid amide-based ones such as acetanilide, acetoanisidide,amide acetate, and benzamide; lactam-based ones such as ε-caprolactam,δ-valerolactam, γ-butyrolactam, and β-propiolactam; acid imide-basedones such as succinic acid imide and maleic acid imide; imidazole basedones such as imidazole, 2-methylimidazole, and 2-ethylimidazole;urea-based ones such as urea, thiourea, an ethylene urea; carbamide acidsalt-based ones such as N-phenylcarbamic acid phenyl and oxazolidone;imine-based ones such as ethyleneimine and a polyethylene imine;oxime-based ones such as formaldoxime, acetoaldoxime, acetoxime,methylethylketoxime, methylisobutylketoxime, and cyclohexanoeoxime;bisulphite-based ones such as sodium bisulphite and potassiumbisulphite, etc., and these may be even as a mixture.

Of those, there are preferred the phenol-based ones, lactam-based ones,alcohol-based ones, and oxime-based ones and, there are particularlypreferred nonylphenol, styrenized phenol, oxybenzoic acid ester,acetoxime, methylethylketoxime, and ε-caprolactam.

In the case that a low temperature (not more than 140° C.) baking isdemanded, particularly, an oxime-based blocking agent is most preferred.

By allowing to react the blocking agent with the highly-branchedpolyisocyanate, the highly-branched block polyisocyanate can beobtained. Reaction of the isocyanate with the blocking agent can beconducted regardless of the presence or absence of solvents.

In the case that the solvents are employed, there must be employedsolvents which are inert to an isocyanate group.

In the reaction for blocking, there may be even employed catalysts suchas organic salts of metals such as tin, zinc, lead, and a tertiaryamine, etc. The reaction can be conducted at −20 to 150° C. and,preferably, 0 to 100° C. In the case of exceeding 100° C., sidereactions are possibly caused and, on the other hand, in the case of toolow temperatures, reaction rate becomes slow, and it is disadvantageous.

The block polyisocyanate to be employed in the present invention has theaverage number of functional group of 4.5-10, preferably, 5-8 per 1molecule of the block polyisocyanate.

The average number of functional group in the block polyisocyanate is anumber of an isocyanate functional group to be statistically possessedin 1 molecule of the block polyisocyanate, and it is calculated by thefollowing equation (1) from a number average molecular weight of thepolyisocyanate before the blocking reaction and an isocyanateconcentration (%). $\begin{matrix}{\frac{\begin{matrix}{( {{Number}\quad {average}\quad {molecular}\quad {weight}} ) \times} \\\frac{( {{isocyanate}\quad {concentrtion}} )}{100}\end{matrix}}{{molecular}\quad {weight}\quad {of}\quad {isocyanate}\quad {group}\quad (42)} = {{Average}\quad {number}\quad {of}\quad {an}\quad {isocyanate}\quad {functional}\quad {group}}} & \text{Equation~~(1)}\end{matrix}$

The acrylic polyol resin (V-A) and the polyisocyanate compound (V-B) inthe present invention are employed as a raw material for a coating,which construct a primary component in the curable resin composition ofthe present invention. Equivalent ratio of the isocyanate group in thepolyisocyanate or the blocked isocyanate group with respect to hydroxylgroup in the resin containing hydroxyl groups is decided according tophysical properties of a coating layer to be desired.

Formulation ratio of the acrylic polyol resin (V-A) with respect to thepolyisocyanate compound (V-B) in the present invention is preferablyNCO/OH=0.8-1.3 (equivalent ratio) from a viewpoint of properties in acoating layer. In the case that the NCO/OH is less than 0.8, residualhydroxyl group occasionally causes a decline of water resistance in acoating layer and, in the case of exceeding 1.3, residual isocyanategroup unpreferably makes the coating layer brittle.

The curable resin composition of the present invention contains 50-90parts by weight of the acrylic polyol resin (V-A) and 10-50 parts byweight of the polyisocyanate compound (V-B) as essential components,provided that total of the (V-A) and the (V-B) does not exceed 100 partsby weight.

Use ratio of the acrylic polyol resin (V-A) with respect to thepolyisocyanate compound (V-B) is 50-10 parts by weight of thepolyisocyanate compound (V-B) with respect to 50-90 parts by weight ofthe acrylic polyol resin (V-A). In the case that the use ratio of theacrylic polyol resin (V-A) is less than 50 parts by weight, a coatinglayer becomes brittle, for example, resulting in that it becomes notappropriate as a coating for a molded article of a polyolefine-basedresin.

On the other hand, in the case that the use ratio of the acrylic polyolresin (V-A) exceeds 90 parts by weight, crosslinking becomesinsufficient and, resulting in that there lower water resistance,solvent resistance, and weatherability. A preferred use ratio of theacrylic polyol resin (V-A) is 60-80 parts by weight, accordingly, apreferred use ratio of the polyisocyanate compound (V-B) becomes 40-20parts by weight

In the present invention, an acidic catalyst for curing is employed inorder to cure by allowing to react the acrylic polyol resin (V-A) withthe polyisocyanate compound (V-B).

Total acid value of in the acidic catalyst for curing is 5-50, andpreferably 15-35. In the case that the total acid value is less than 5,crosslinking reactivity lowers, resulting in that crosslinking becomesinsufficient, and there lower gasoline resistance and weatherability.

On the other hand, the acid value is higher than 50, there lower storagestability and water resistance.

As described hereinabove, a coating composition can be changed to alower temperature curability by controlling the acid value. As such theacidic catalyst for curing, a weak acidic catalyst is employed. As suchthe weak acidic catalyst, for example, there are enumerated phosphoricacids, a monophosphate, a phosphite, a phosphate having an unsaturatedgroup, and carboxylic acids, etc.

As the weak acidic catalyst, the phosphoric acids and phosphates areparticularly preferred. As such the phosphoric acids and phosphates, forexample, there are enumerated phosphoric acid, pyrophosphoric acid,etc., and mono or diphosphates, etc. As the monophosphates, for example,there are enumerated monooctyl phosphate, monopropyl phosphate, andmonolauryl phosphate, etc. As the diphosphates, for example, there areenumerated dioctyl phosphate, dipropyl phosphate, and dilaurylphosphate, etc.

The acidic catalyst for curing is employed in an amount of 0.001-10% byweight, and preferably 0.001-5% by weight based on total weight of theacrylic polyol resin (V-A) and the polyisocyanate compound (V-B).

In the case that the polyisocyanate is prepared as a block type, it is asingle-liquid type and, although there can be solved a problemconcerning storage stability, dissociation temperature of the blockingagent becomes high and, it must become occasionally heated to not lessthan 150° C., and there is occasionally caused a problem thatcompatibility with a base resin is not sufficient and, an outerappearance in finishing becomes worse in a coating layer.

In the cases, the polyisocyanate compound to be employed in the presentinvention is preferably employed as a self-crosslinkable type resinwhich simultaneously contains a block isocyanate group and hydroxylgroup in a molecule, which is described hereinafter.

The self-crosslinkable type resin is comprised a product in which avinyl polymer having a block isocyanate group in a molecule is connectedto a polyol resin having hydroxyl group in the molecule through urethanebond and, for example, it is obtained by (I) allowing to react a portionof hydroxyl groups in the polyol resin (A0) having at least two hydroxylgroups in the molecule with a portion of free isocyanate groups in avinyl polymer (B0) having at least two free isocyanate groups in themolecule, and then, allowing to react a blocking agent with residual allthe free isocyanate groups, or (II) allowing to react a portion ofhydroxyl groups in the polyol resin (A0) having at least two hydroxylgroups in the molecule with all of free isocyanate groups in a vinylpolymer simultaneously having free isocyanate groups and blockisocyanate groups in the molecule.

The vinyl polymer (B0) is a vinyl polymer having at least two freeisocyanate groups in the molecule and, specifically, it is a polymer inwhich a vinyl monomer containing isocyanate group (hereinafter,abbreviated as “NCO group-contained monomer”) is employed as anessential component, and further, other monomers are optionallyemployed, and which has isocyanate groups at terminals and/or sidechains in a linear chain polymer.

The NCO group-contained monomer is a compound having at least one of anonblocked free isocyanate group and at least one of aradically-polymerizable double bond, respectively.

For example, there are employed at least one or two kinds selected fromisocyanatemethyl methacrylate, 2-isocyanate ethylmethacrylate, m- orp-isopropenyl-α,α′-dimethylbenzyl isocyanate, and a 1:1 (molar ratio)adduct of a vinyl monomer having hydroxyl group with a diisocyanatecompound, etc.

The diisocyanate compound has two isocyanate groups in the molecule, andthere are enumerated the above-described aliphatic, aromatic, orcycloaliphatic-based diisocyanate compounds.

Of the above compounds, a preferred compound as the NCO group-containedmonomer is 2-isocyanate ethylmethacrylate,m-isopropenyl-α,α′-dimethylbenzyl isocyanate, and an equimolar adduct of2-hydroxyethylacrylate with isophorone diisocyanate, etc.

The vinyl monomer having hydroxyl group, which is employed for preparingthe NCO group-contained monomer, is a compound having at least onehydroxyl group and at least one radically-polymerizable double bond,respectively, in the molecule, for example, there are enumerated2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,hydroxybutylacrylate, 2,3-dihydroxypropylacrylate,2-hydroxy-3-phenoxyethylacrylate, and 2-hydroxy-3-ethoxyethylacrylate,etc. Further, there is enumerated an equimolar adduct of acrylic acid ormethacrylic acid with a glycol (a carbon number of 2-20), etc.

The vinyl polymer (B0) is obtained by polymerizing the NCOgroup-contained monomer alone or by copolymerizing the monomer withother vinyl monomers.

As the other vinyl monomers, there is preferred a compound whichcontains one radically-polymerizable double bond in the molecule and,moreover, which does not contain an active hydrogen which can react withisocyanate group, specifically, there are enumerated aromaticvinyl-based monomers such as styrene, α-methylstyrene, and vinyltoluene;(meth)acrylates such as methyl(meth)acrylate, ethyl(meth)acrylate,butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, lauryl(meth)acrylate,tridecyl (meth)acrylate, stearyl(meth)acrylate,cyclohexyl(meth)acrylate, and benzyl(meth)acrylate; a fluorine-containedvinyl-based monomer such as Viscose 3F (a trade name, manufactured byOsaka Yuki Kagaku, Ltd., hereinafter, it shows a same mean), Viscose3MF, Viscose 8F, Viscose 8MF, perfluorocyclohexyl(meth)acrylate,N-2-propylperfluoro octane sulphonic amide ethyl(meth)acrylate,vinylfluoride, and vinylidene fluoride; a nitrogen-contained vinylmonomer such as N,N′-diethylaminoethyl(meth)acrylate,N,N′-diethylaminoethyl(meth)acrylate, N,N′-diethylaminoethyl(meth)acrylate, and N,N′-diethyl(meth)acrylic amide; a vinylether-basedmonomer such as vinylethylether and vinylbutylether; andglycidyl(meth)acrylate, 3,4-epoxycyclohexylmethyl(meth)acrylate, analkyletherized compound such as arylglycidyl ether and methylol acrylicamide, (meth)acrylic amide, (meth)acrylic chloride, vinylchloride,vinylidenechloride, (meth)acrylonitrile, and γ-methacryloxyalkyltrimethoxy silane, etc., and these are employed solely or as a mixtureof two or more kinds.

Ratio of the NCO group-contained monomer with respect to the other vinylmonomers, if it is within a range containing at least two freeisocyanate groups in one molecule of the polymer (B0), is notparticularly limited, and the NCO group-contained monomer/the othervinyl monomers (weight ratio) ranges in 100/0-1/99, preferably65/35-30/70.

Further, in usual, a polymerization reaction of the NCO group-containedmonomer alone or a copolymerization reaction of the other vinyl monomersis preferably conducted in an inert organic solvent not having an activehydrogen which can react with isocyanate group. As such the inertorganic solvent, there are employed the above-described solvent or amixture thereof. Since the solvents occasionally contain moisture, themoisture is optionally in advance removed.

The (co)polymerization reaction is usually conducted at a temperature of50-180° C. using a radical polymerization initiator, a molecular weightof the polymer (B0) can be controlled by a reaction concentration andthe amount of the radical polymerization initiator, etc. The reactionconcentration ranges in 20-80% by weight as a polymer. Particularly, inorder to elevate a polymerization ratio, there is employed aperoxide-based or carbonate-based polymerization initiator, and thereaction is preferably conducted at a temperature of not less than 100°C.

More preferably, there is apt to be obtained a polymer having a highpolymerization ratio by employing together an acrylate-based monomer.Concentration of the polymerization initiator ranges in 0.01-15% byweight based on total monomers, and it preferably ranges in 0.1-10% byweight.

Further, it can be also polymerized by utilizing an electron beam orultraviolet ray in place of employing the polymerization initiator.

Still further, other than a radical polymerization, there can be alsoutilized an ion polymerization method and a group transferpolymerization method.

In the polymer (B0) to be employed in the present invention, a weightaverage molecular weight ranges in preferably 1000-100000 and,particularly, preferably 3000-30000. Further, an isocyanate valueappropriately ranges in 30-200 g/1000 g of a resin.

The polymer (B0) has at least two free isocyanate groups in the moleculeand, preferably, it does not have at all an active hydrogen which canreact with isocyanate group.

The polyol resin (A0): It is a resin having at least two hydroxyl groupsin the molecule. Specifically, there are enumerated an acrylic resin(A0-1), a polyester resin (A0-2), and a fluorocarbon resin (A0-3), etc.which have at least two hydroxyl groups in the molecule, and all of thealready-known products can be employed, provided that the polyol resin(A0) contains the above-described polyol resins (A) in a proportion of0.5-80 parts by weight.

First of all, the acrylic resin (A0-1) is an acrylic-based resin havingat least two hydroxyl groups in the molecule. The acrylic resin (A0-1)is a polymer which containing a monomer unit (hereinafter, referred to“hydroxyl group-contained monomer”) having at least one of hydroxylgroups and at least one of radically-polymerizable double bonds,respectively, in the molecule as an essential component, and in whichother vinyl monomers are further employed, and which does not containthe the NCO group-contained monomer.

As the hydroxyl group-contained monomer, for example, there areenumerated 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate,hydroxybutylacrylate, 2,3-dihydroxypropyl acrylate,2-hydroxy-3-phenoxyethylacrylate, and 2-hydroxy-3-ethoxyethylacrylate,etc. Further, there is enumerated an equimolar adduct of acrylic acid ormethacrylic acid with a glycol (a carbon number of 2-20), etc., acaprolactone-modified(meth)acrylate such as Placcel FM-1, FM-2, FM-3,FM-4, FM-5, FA-1, FA-2, FA-3, FA-4, and FA-5 (which are manufactured byDaicel Chemical Industries, Ltd., a trade name, hereinafter, the same),and the hydroxyalkyl(meth)acrylate composition modified by a smallamount of lactones, in which a proportion of monomers having not lessthan 2 continuous chains (n≧2) of lactones is less than 50% of thepresent invention, etc. These may be also employed as a mixture of twoor more kinds.

The other monomers, which can be copolymerized with the hydroxylgroup-contained monomer, have a radically-polymerizable double bond inthe molecule and, moreover, do not preferably contain an active hydrogenwhich can react with isocyanate group, specifically, there are preferredthe vinyl monomers enumerated as other monomers in the illustration forthe above-described vinyl polymer (B0).

Further, the acrylic resin (A0-1) is a resin essentially containing a(meth)acrylate (also including the hydroxyl group-contained monomer),etc., and the content thereof is preferably 20-100% by weight and,particularly, preferably 30-100% by weight in total monomers employedfor the preparation of the acrylic resin (A0-1).

Construction ratio of the above-described monomers in the acrylic resin(A0-1) is not particularly limited, and the hydroxyl group-containedmonomer is 1-100% by weight and, particularly, 10-60% by weight, a vinylmonomer having a carboxylate group is 0-20% by weight and, particularly,0-5% by weight, and other vinyl monomers are 0-99% by weight and,particularly, preferably 40-90% by weight based on total weight of themonomer composition.

The acrylic resin (A0-1), as exemplified in the preparation of thepolymer (A), can be obtained by a radical polymerization method using apolymerization initiator, a photo-polymerization method utilizing anelectron beam or an ultraviolet ray, an ionic polymerization method, anda group transfer polymerization method,

As organic solvents to be employed in the polymerization methods, thereis preferred an inert organic solvent not containing an active hydrogenwhich reacts with isocyanate group and, specifically, there arepreferred the solvents exemplified in the item of the above-describedblock type isocyanate, and there are also preferred hydrophilic orwater-soluble solvents not having an active hydrogen, for example, thereare preferred diethyleneglycol dimethylether and ethyleneglycoldimethylether, etc.

On the other hand, in the case that the acrylic resin (A0-1) issynthesized in an organic solvent having an active hydrogen, it can beemployed in a urethanation reaction with the polymer (A0) after removingthe organic solvent under a reduced pressure or by condensing or spraydrying.

In the acrylic resin (A0-1), a weight average molecular weight ranges inpreferably 500-50000 and, particularly, preferably 2000-35000 and,hydroxyl group particularly appropriately ranges in 5-250 based on ahydroxyl value.

The polyester resin (A0-2) is a polyester-based resin having at leasttwo hydroxyl groups in the molecule. The polyester resin (A0-2) isobtained by an esterification or transesterification reaction using apolybasic acid having at least two carboxylic groups in the molecule anda polyvalent alcohol having at least two hydroxyl groups in the moleculeas essential components and, optionally, using a fatty acid and/or afatty acid ester as raw materials, so that free hydroxyl groups arecontained.

As the polybasic acid and the polyvalent alcohol, for example, there areenumerated the polybasic acid and the polyvalent alcohol for thepolyester polyols exemplified in the item of the block type isocyanate.

As the fatty acids, for example, there can be employed a (semi)dryingoil fatty acid such as a safflower oil fatty acid, a linseed oil fattyacid, a soybean oil fatty acid, an eno oil fatty acid, a corn oil fattyacid, a tall oil fatty acid, a sunflower oil fatty acid, a cotton seedoil fatty acid, and a tung oil fatty acid; a coconut oil fatty acid; anolive oil fatty acid; and a palm oil fatty acid, etc. of those, the(semi)drying oil fatty acid is preferably employed from a viewpoint ofan improvement of properties in a coating layer.

In the polyester resin (A0-2), in general, an acid value (mgKOH/g of aresin) desirably ranges in not more than 200 and, preferably not morethan approximately 100, and a hydroxyl value (mgKOH/g of a resin) rangesin approximately 5-400 and, preferably approximately 20-250. In the casethat the hydroxyl value is less than approximately 5, curability in acoating layer lowers, and there is unpreferably observed a tendency of adecline of properties in a coating layer such as hardness and bendingresistance and, on the other hand, in the case that the hydroxyl valuebecomes more than approximately 400, there is unpreferably observed adecline of properties in a coating layer such as water resistance andcorrosion resistance.

Introduction of hydroxyl groups into the polyester resin (A0-2) ispreferably conducted by employing together a compound having at leastthree hydroxyl groups in the molecule, for example, as the polyvalentalcohol.

Further, in the polyester resin (A0-2), a weight average molecularweight ranges in generally approximately 500 to approximately 50000, andpreferably approximately 1000 to approximately 30000 and, a softeningpoint is not more than 150° C., and preferably not more thanapproximately 115° C.

The esterification reaction by respective components for the preparationof the polyester resin (A0-2) is preferably conducted under the presenceof an organic solvent. As the organic solvent to be employed in theesterification reaction, there is preferred an inert organic solvent nothaving an active hydrogen which reacts with isocyanate group inconsideration of an introduction of urethane bond derived from aurethane reaction with the vinyl polymer (B0) and, specifically, thereare preferred the solvents exemplified in the item of theabove-described block type isocyanate, and there are also preferredhydrophilic or water-soluble solvents not having an active hydrogen, forexample, there are preferred diethyleneglycol dimethylether andethyleneglycol dimethylether, etc.

On the other hand, in the case that the polyester resin (A0-2) havinghydroxyl groups is synthesized in an organic solvent having an activehydrogen, it can be employed in a urethanation reaction with the polymer(B0) after removing the organic solvent under a reduced pressure or bycondensing or spray drying.

Further, as the polyester resin (A0-2) having hydroxyl groups, there canbe also employed a ring-opened polymer of ε-caprolactone and, as aspecific example thereof, there are enumerated Placcel 208, 240, 305,and 308 which are manufactured by Daicel Chemical Industries, Ltd.

The fluorocarbon resin (A0-3) is a resin having at least two hydroxylgroups, and hving fluorine atoms at a main structure or side chains.

The fluorocarbon resin (A0-3) is obtained by allowing to copolymerizepartially or wholly employing a fluorine-contained polymerizableunsaturated monomer as other vinyl monomers which are occasionallyemployed for the preparation of the acrylic resin (A0-1) with thehydroxyl group-contained monomer.

As the fluorine-contained polymerizable unsaturated monomer, forexample, there are enumerated a fluoroolefine represented by a generalformula CX₂═CX₂ (in the formula, X may be identical to or different fromeach other, and represents H, Cl, Br, F, an alkyl group or haloalkylgroup, provided that it contains at least one piece of F): aperfluoroalkyl(meth)acrylate such as a perfluorobutylethyl(meth)acrylate, a perfluoroisononyl ethyl(meth)acrylate, aperfluorooctyl ethyl(meth)acrylate, Viscose 3MF, Viscose 8F, Viscose8MF, perfluorocyclohexyl(meth)acrylate, and N-2-propylperfluoro octanesulphonic amide ethyl(meth)acrylate, etc.

In the fluorocarbon resin (A0-3), properties such as a hydroxyl valueand a weight average molecular weight may be nearly identical to theabove-mentioned acrylic resin (A0-1).

In the preparation of the self-crosslinkable resin (I), a reaction ofthe vinyl polymer (B0) with the polyol resin (A0) is a urethanationreaction of isocyanate group with hydroxyl group and, specifically, theurethanation reaction is conducted by formulating the polyol resin (A0)into an organic solution of the vinyl polymer (B0) at a temperature ofusually 20-100° C., and preferably 25-60° C.

The reaction is controlled by the reduction amount of isocyanate group,that is, an isocyanate value. Further, in the reaction, a tin-basedcatalyst, etc. may be optionally even employed. Formulating amount ofthe polyol resin (A0) appropriately ranges in 0.1-10.0, and preferably0.5-5.0 based on a functional group ratio in the vinyl polymer (B0) withrespect to the polyol resin (A0), that is, NCO/OH ratio and, based ontotal weight of the both, the vinyl polymer (B0) ranges in 1-99% byweight, and preferably 10-70% by weight, the polyol resin (A0) ranges in1-99% by weight, and preferably 30-90% by weight, provided that thepolyol resin (A0) contains 0.5-80 parts by weight of the acrylic polyolresin (V-A) obtained using the hydroxyethyl(meth)acrylate compositionmodified by a small amount of lactones of the present invention withrespect to 0.5-50 parts by weight of the polyisocyanate compound (V-B).

Further, formulation is conducted so that at least average 0.1 piece ofurethane bond is introduced with respect to 1 molecule of the vinylpolymer (B0) having a weight average molecular weight of 500-50000, andpreferably, average 0.5-1.5 piece of urethane bond is introduced withrespect to 1 molecule of the vinyl polymer (B0) having a weight averagemolecular weight of 500-30000 and, particularly, 1 piece of urethanebond is most preferably introduced with respect to 1 molecule of thevinyl polymer (B0).

Further, in the preparation of the self-crosslinkable resin (I),gelation in the reaction with the polyol resin (A0) can be prevented byemploying the vinyl polymer (B0) containing m-isopropenyl-α,α′-dimethylbenzyl isocyanate having a tertiary isocyanate group as avinyl polymer (B0), whereby, a coating layer can be preferably cured ata low temperature.

As described hereinabove, urethane bonds are introduced by allowing toreact the polyol resin (A0) and, the self-crosslinkable resin (I) isobtained by completely blocking the residual free isocyanate group whichis contained in the vinyl polymer (B0) in which the polyol resin (A0) isadded through allowing to react with a blocking agent. As the blockingagent, for example, there are enumerated the compounds describedhereinabove.

In principle, the blocking agent is preferably formulated in an amountto be required so as to react with all residual free isocyanate groups.

Reaction of a polymer in which the polyol resin (A0) is added with theblocking agent is usually conducted at a temperature of 20-100° C.Further, a tin-based catalyst may be even optionally employed.

The self-crosslinkable resin (II) is a self-crosslinkable resinsimultaneously containing a block isocyanate group and hydroxyl groupcoexist in the molecule, and which is prepared by allowing to partiallyreact hydroxyl groups in the polyol resin (A0) having at least twohydroxyl groups with all the free isocyanate groups in a vinyl polymer(V-C) in which free isocyanate groups and block isocyanate groupscoexist in the molecule.

The vinyl polymer (V-C) is a vinyl polymer simultaneously containingfree isocyanate groups and block isocyanate groups coexist in themolecule and, specifically, it is obtained by allowing to partiallyreact free isocyanate groups in the above-described vinyl polymer (B0)with a blocking agent. In relation to the vinyl polymer (B0) to beemployed for the preparation of the vinyl polymer (V-C), as an NCOgroup-contained monomer, the above-described monomers can be employedand, particularly, there is preferred a vinyl polymer (B0) obtained byusing an equimolar adduct of 2-isocyanate ethylmethacrylate,m-isopropenyl-α,α′-dimethylbenzyl isocyanate, and 2-hydroxyethylacrylatewith isophorone diisocyanate.

Formulating amount of the blocking agent into the polymer may be anamount to be required for remaining the free isocyanate groups so thatan introducing amount of urethane bonds derived from a reaction with thepolyol resin (A0) in a succeeding step becomes a same level as in theabove-described self-crosslinkable resin (I) and, particularlypreferably, a reaction is preferably conducted by allowing to remainfree isocyanate group being capable of introducing one piece of urethanebond per one molecule of the polymer (V-A) and by formulating an amountof the blocking agent to be required for completely blocking theremained free isocyanate.

And, the self-crosslinkable resin (II) is obtained by allowing topartially react hydroxyl groups in the polyol resin (A0) with all theremained free isocyanate in the polymer obtained by allowing to reactthe blocking agent with a polymer. In other words, it is required thatthe amount of the hydroxyl groups in the resin (A0) is larger than theamount of the remained free isocyanate.

The reaction with the blocking agent for obtaining theself-crosslinkable resin (II) and the reaction of the polymer obtainedwith the resin (A0) are likewise conducted as illustrated in theself-crosslinkable resin (I).

In the self-crosslinkable resins (I) and (II), a molecule of a resincontaining a block isocyanate group is connected to a molecule of thepolyol resin through a urethane bond derived from a reaction ofisocyanate group with hydroxyl group. Accordingly, those are also lookedupon as a graft polymer by the both molecules.

Thus-obtained self-crosslinkable resins (I) and (II) have at least onepiece of the block isocyanate group and one piece of hydroxyl group, anda weight average molecular weight is 1000-120000 or so and,particularly, preferably 5000-50000 or so.

In the self-crosslinkable resins to be employed in the presentinvention, crosslinking degree becomes highest as a self-crosslinkablecoating layer by adjusting the amount of the block isocyanate group andhydroxyl group in the molecule to an equimolar amount, and hydroxylgroup is preferably adjusted to an excessive amount in consideration ofadhesion of a intermediate coating layer to a substrate and an overcoating layer. In the resins, a hydroxyl value (mgKOH/g of a resin)appropriately ranges in 10-200, an isocyanate value (g/1000 g of aresin) appropriately ranges in 15-150, and an acid value (mgKOH/g of aresin) appropriately ranges in not more than 200.

Coating in relation to the present invention contains theabove-described curable resin composition as an essential component, andit is obtained by dissolving or dispersing the resin into an organicsolvent or a water-based solvent and, optionally, there can beappropriately formulated a variety of additives which are conventionallyemployed in a coating field, for example, an ultraviolet ray absorbent,a photo-stabilizer, an antioxidant, a pigment for coloring, an extenderpigment, a metallic pigment, an aluminum powder, a pearly mica powder,an anti-dropping agent or an anti-sedimentation agent, a leveling agent,a dispersant, a defoaming agent, an antistatic agent, a catalyst forcuring, a flowability-adjusting agent, a cellulose acetate-butylate, anda thinner which are publicly- and commonly-known to prepare a two-liquidtype coating or a single-liquid type coating composition.

Further, there can be employed other resins such as an epoxy resin and apolyester resin or a high molecular weight compound which has a goodcompatibility within a range in which an effect by the present inventionis not decreased. Thus-obtained coating can be coated by publicly- andcommonly-known methods such as spray coating, roller coating, and brushcoating. It is to be noted that it goes without saying that the resincomposition for a coating of the present invention can be employed as aclear coating in which pigments are not employed, or an enamel coatingin which pigments are employed.

In the coating in relation to the present invention, there can beactualized a more exceedingly excellent acid resistance which does notinclude any practical problems compared to a coating prepared from aconventional polyol and melamine resin even though being furtheremployed together with other polyols and crosslinking agents (forexample, a melamine resin). In the coating in relation to the presentinvention, in the case of simultaneously employing other polyol resinsand melamine resins, the content of the curable resin composition of thepresent invention is not less than 10% by weight, and preferably notless than 25% by weight in total solid resin components, the content ofthe melamine resins are not more than 30% by weight, and preferably notless more than 20% by weight, in total solid resin components.

In the case that the curable resin composition of the present inventionis less than 10% by weight or, the melamine resins are more than 30% byweight, an acid resistance cannot be unpreferably elevated.

As the melamine resins to be simultaneously employed, usual melamineresins for coatings can be employed without any modification, and iminotype or methylol type melamine resins are employed. The imino type ormethylol type melamine resins are not particularly limited in employingand, if those are resins to be employed for a coating-system in whichhydroxyl group is employed as a functional group. As such the imino typemelamine resins, for example, there are enumerated Yuban 22R (solidcontent of 60%), Yuban 21R (solid content of 50%), and Yuban 2028 (solidcontent of 75%) which are manufactured by Mitsui Kagaku (all of thoseare a imino type melamine resin), etc. On the other hand, as themethylol type melamine resins, there can be employed a melamine resinhaving a condensation degree of 1.1-20 or so which is prepared usingmelamine, formaldehyde, a monoalcohol of a carbon number of 1-4, andoptionally water as raw materials. For example, there are enumeratedYuban 60R (solid content of 50%) manufactured by Mitsui Kagaku andSuperbekkamine L-121-60 (solid content of 60%) manufactured by DainipponInk Kagaku Kogyo, Ltd., etc.

As the polyol resins to be employed together with the curable resincomposition of the present invention, for example, there are preferredthe above-described acrylic resin (A0-1), polyester resin (A0-2), andfluorine resin (A0-3).

Provided, in the case of simultaneously employing the polyol resins, thepolyol resins and the polyol resins (A0) definitively contain theacrylic polyol resin (V-A) in a proportion of 0.5-80 parts by weightwith respect to 0.5-50 parts by weight of the polyisocyanate compound(V-B).

In the curable resin composition of the present invention, above all, inorder to elevate weatherability such as retention of a gloss duringexposure and a high extentionable property, there is preferably employeda mixture composed of an ultraviolet ray absorbent/hindered amine-basedphoto-stabilizer=(40-60)/(60-40) (ratio of solid components) within arange of 0-10 wt % based on solid components in the acrylic polyol resin(V-A). In the case that addition amount is not less than 10 wt %, sincea price of a coating becomes expensive and, crystallines areoccasionally formed at a low temperature and water resistanceoccasionally lowers, and a resin solution occasionally discolors, it isnot preferred so much. Even in an outside value of the above mixingratio of the ultraviolet ray absorbent with respect to the hinderedamine-based photo-stabilizer, although an effective action is observed,the effective action is most excellently observed in a range of theabove mixing ratio.

As typical examples of the ultraviolet ray absorbent, there can bepreferably employed benzophenone, 2,4-dihydrobenzophenone,2,2′,4,4′-tetrahydroxy benzophenone, 2-hydroxy-4-methoxybenzophenone,2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2′-dihydroxybenzophenone,2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone,2-hydroxy-4-methoxy-5-sulphobenzophenone,5-chloro-2-hydroxybenzophenone,2,2′-dihydroxy-4,4′-dimethoxy-5-sulphobenzophenone,2-hydroxy-4-methoxy-2′-carboxybenzophenone, and2-hydroxy-4-(2-hydroxy-3-methyl-acryloxyisopropoxy)benzophenone;2-(2′-hydroxy-5-methyl-phenyl)-benzotriazole,2-(2-hydroxy-3,5-di-t-amyl-phenyl)-2H-benzotriazole,2-(2′-hydroxy-3′,5′-di-t-butyl-phenyl)benzotriazole,2-(2′-hydroxy-3′,5′-di-t-butyl-phenyl)-5-methyl-benzotriazole,2-(2′-hydroxy-3′,5′-di-t-butyl-phenyl)-5-chloro-benzotriazole,2-(2′-hydroxy-3′,5′-di-t-isoamyl-phenyl)benzotriazole, and(2-hydroxy-5-t-butyl-phenyl)benzotriazole; phenylsalicylate,4-t-butyl-phenylsalicylate, and p-octyl-phenylsalicylate;ethyl-2-cyano-3,3′-diphenylacrylate,2-ethylhexyl-2-cyano-3,3′-diphenylacrylate;hydroxy-5-methoxy-acetophenone, 2-hydroxy-naphtophenone;2-ethoxyethyl-p-methoxycinnamate; nickel-bisoctylphenylsulphide; andanilide oxalate, etc., for example, a benzotriazole-based ultravioletray absorbent such as Tinuvin 900, Tinuvin 383, and Tinuvin P(manufactured by Ciba Geigy), an anilide oxalate-based ultraviolet rayabsorbent such as Sandbar 3206 (manufactured by Sand), etc. A fixedamount of the absorbents may be added in a terminating period of acopolymerization reaction of the acrylic polyol or in the preparation ofa coating. On the other hand, in the case of T-17, T-37, and T-38 (allof those are a product by Adeka Argus Kagaku, Ltd.) which are a reactiveultraviolet ray absorbent containing an organic group having anultraviolet ray absorbing ability such as an O-hydroxybenzophenone groupand an ethylenic copolymerizable unsaturated bond such as methacrylicacid group in an identical molecule, a fixed amount thereof may besimultaneously introduced by copolymerizing at a copolymerization stepof the acrylic polyol resin (A) components.

As examples of the hindered amine-based photo-stabilizer, there can bepreferably employed a piperidine-based one which is usually called HALS(HALS) and typically includes4-benzoyloxy-2,2,6,6-tetramethylpiperidine,bis(2,2,6,6-tetramethyl-4-piperidine)sebacate, or Tinuvin 144, 292, and765 (all of those are a product manufactured by Ciba Geigy, A.G.), MARKLA-57, 62, 63, 67, and 68 (all of those are a product by Adeka ArgusKagaku, Ltd.), Sanol LS292 (manufactured by Sankyo), and Sandbar 3058(manufactured by Sand). A fixed amount of the stabilizers may be addedin a terminating period of a copolymerization reaction of the acrylicpolyol resin (A) or in the preparation of a coating. In the case of ahindered amine-based compound containing an organic group having aphoto-stabilizing ability and an ethylenic copolymerizable unsaturatedbond such as (meth)acrylic acid group such as the MARK LA-82, 87, andT-41 (all of those are a product by Adeka Argus Kagaku, Ltd.), a fixedamount thereof may be simultaneously introduced by copolymerizing at asynthesis step of the acrylic polyol resin (A) components.

Further, in order to increase an effectiveness thereof, optionally therecan be simultaneously employed an antioxidant such as “Sumilizer BHT” (aproduct manufactured by Sumitomo Kagaku Kogyo, Ltd.), “Seenox BCS” (aproduct manufactured by Shiroishi Calcium, Ltd.), “Iranox 1010 or 1076”(a product manufactured by Ciba Geigy, A.G.), “Noclizer TNP” (a productmanufactured by West Germany/Bayer, A.G.), which are well known andcommonly-used.

As the catalysts for curing, there are enumerated a phosphate, anorganic acid such as dodecylbenzene sulphonic acid or paratoluenesulphonic acid and an amino acid thereof, an organic tin compound suchas dibutyltin dilaurate and dibutyltin maleate and a chelating compoundthereof, etc.

As the coloring pigments, extender pigments, leveling agents,dispersants, defoaming agents, photostabilizers, thinners, andantistatic agents, for example, there are enumerated ones exemplified inthe above-described present invention III.

In the case of preparing a coating composition using the curable resincomposition of the present invention, there are mixed the acrylic polyolresin (V-A), the polyisocyanate compound (V-B), and optionally,additives such as acidic-dissociation catalysts and pigments, anduniformly dispersed by a dispersing machine such as a sand grind mill, aball mill, and Atlighter to prepare a curable type coating composition.

Coating of the coating composition obtained as described hereinabove maybe conducted according to the methods illustrated in the presentinvention III.

VI

Hereinafter, the present invention VI is illustrated.

The present invention VI is a curable resin composition comprising anacrylic polyol resin (VI-A) obtained by using ahydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones, in which a proportion of monomers having not less than 2continuous chains (n≧2) of lactones represented by the general formula(1) is less than 50% (GPC area %), and a polyisocyanate compound (VI-B).

The hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactones to be employed in the present invention is asillustrated in the present invention I.

By allowing to polymerize alone the hydroxyalkyl (meth)acrylatecomposition (a) modified by a small amount of lactones to be employed inthe present invention or by allowing to copolymerize with otherradically-polymerizable monomers, there can be provided a curableacrylic polyol which is excellent in reactivity with a crosslinkingagent and rich in flexibility, and it can be utilized as a material forthe curable resin composition for coating of the present invention.

In the present invention, the other radically-polymerizable monomers areemployed to copolymerize with the lactone-modified (meth)acrylate havinghydroxyl group. The acrylic polyol resin (VI-A) in relation to thepresent invention is a vinyl copolymer having carboxylic group and acrosslinkable functional group, which is obtained by allowing to react ahydroxyalkyl(meth)acrylate composition (a) modified by small amount oflactones with a vinyl monomer having carboxylic group and othervinyl-based monomers.

As the vinyl-based monomer having carboxylic group to be employed in thepresent invention, only particularly typical examples are exemplified,and which include an α,β-ethylenic unsaturated carboxylic acid such asacrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleicacid (anhydride) or fumaric acid (anhydride), itaconic acid, itaconicanhydride, and citraconic acid.

As the other vinyl-based monomer, there are enumerated a polymerizablevinyl monomer containing an active hydrogen and other polymerizableunsaturated monomers, and the following compounds are exemplified.

As a (meth)acrylate, for example, an alkyl or cycloalkyl ester having acarbon number of 1-20 of a (meth)acrylic acid such asmethyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,isopropyl(meth)acrylate, butyl(meth)acrylate, hexyl(meth)acrylate,2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, lauryl(meth)acrylate,tridecyl(meth)acrylate, stearyl (meth)acrylate,cyclohexyl(meth)acrylate, isobonyl(meth)acrylate, andadamantyl(meth)acrylate; a (meth)acrylate such as benzyl(meth)acrylate;an alkoxyalkyl ester having a carbon number of 2-8 of a (meth)acrylicacid such as methoxybutyl(meth)acrylate, methoxyethyl(meth)acrylate, andethoxybutyl(meth)acrylate; a fluorine-contained vinyl monomer such asViscose 3F, 3MF, 8F, and 8MF (manufactured by Osaka Yuki Kagaku, Ltd., atrade name), perfluorocyclohexyl(meth)acrylate, N-2-propylperfluorooctane sulphonic amide ethyl(meth)acrylate, vinylfluoride, andvinylidene fluoride; a nitrogen-contained vinyl monomer such asN,N′-diethylaminoethyl(meth)acrylate,N,N′-diethylaminoethyl(meth)acrylate, N,N′-diethylaminoethyl(meth)acrylate, and N,N′-diethyl(meth)acrylic amide; a vinylether-basedmonomer such as vinylethylether and vinylbutylether; andglycidyl(meth)acrylate, 3,4-epoxycyclohexylmethyl(meth)acrylate, analkyletherized compound such as arylglycidyl ether and methylol acrylicamide, (meth)acrylic amide, (meth)acrylic chloride, vinylchloride,vinylidenechloride, (meth)acrylonitrile, and γ-methacryloxyalkyltrimethoxy silane, an aromatic vinyl monomer such as styrene,α-methylstyrene, and vinyltoluene; (meth) acrolein, butadiene, isoprene,methylisopropenyl ketone, etc., and these are employed solely or as amixture of two or more kinds.

As the polymerizable monomer having an active hydrogen, there areenumerated a (meth)acrylate having hydroxyl group described below and a(meth)acrylate having amino group, these can be employed in mixing.

As the (meth)acrylate having hydroxyl group, for example, there areenumerated hydroxyalkyl(meth)acrylates having a carbon number of 2-8such as hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate,hydroxybutylacrylate, 2,3-dihydroxypropylacrylate,2-hydroxy-3-ethoxyethylacrylate, 2-hydroxy-3-ethoxyethylacrylate, etc.,an equimolar adduct of acrylic acid or methacrylic acid with a glycol (acarbon number of 2-20), etc., and a caprolactone-modified(meth)acrylatesuch as Placcel FM-1, FM-2, FM-3, FM-4, FM-5, FA-1, FA-2, FA-3, FA-4,and FA-5 (manufactured by Daicel Chemical Industries, Ltd., a tradename).

These may be also employed as a mixture of two or more kinds.

As the (meth)acrylate having amino group, there are enumeratedaminoalkyl(meth)acrylates such as dimethylaminoethyl (meth)acrylate anddiethylaminoethyl(meth)acrylate; and a (meth)acryl amide, etc., thosecan be employed solely or in mixing of two or more kinds.

The above-described other vinyl monomers can be also employed in mixing,and can be selected according to a desired physical property.

The acrylic polyol resin (V-A) to be employed in the present inventionis prepared by radically-polymerizing under the presence of a radicalpolymerization initiator by publicly-known solution polymerizationmethods.

As the radical polymerization initiator, there can be employed aperoxide initiator such as benzoyl peroxide, t-butylhydroperoxide,cumylhydroperoxide, cumenhydroperoxide, t-butyl peroxybenzoate, andt-butylperoxy-2-ethylhexanoate, and an azo-based initiator such asazobisisobutyronitrile and azobisdimethylvaleronitrile.

As solvents to be employed in the solution polymerization, for example,there are enumerated aromatic hydrocarbons such as benzene, toluene, andxylene; ester-based ones such as ethyl acetate, propyl acetate, butylacetate, and cellosolve acetate; ether-based ones such as dioxane, andethylene glycol dibutylether; ketones such as acetone,methylethylketone, and methyl isobutyl ketone. The solvents may beemployed solely or in combination of two or more kinds.

As a reaction vessel to be employed for the above-describedpolymerization, there is preferably employed a reaction vessel equippedwith an agitation and a reflux condenser equipped with a drying tube,and a twin-screw extruder.

Polymerization temperature and polymerization time of period depend uponrespective kinds and feeding ratio of the hydroxyalkyl(meth)acrylatecomposition modified by a small amount of lactones of the presentinvention, the above-described vinyl-based monomer having carboxylicgroup, the above-described other vinyl-based monomer, a kind and anamount of the catalysts, reaction apparatuses, and those are notparticularly limited, and those are appropriately decided by the use ofa desired curable oligomers or (co)polymerized acrylic resins, andphysical properties of a coating layer in the case of a coating. Suchthe polymerization reaction is conducted at a temperature of 60-150° C.or so using the usual radical polymerization initiator in the organicsolvents.

In the acrylic polyol resin (VI-A) to be employed in the presentinvention, since there can be readily designed a molecular weight,composition, and a structure, and it is excellent in weatherability, itcan provide novel crosslinked particles which can be applied in wideuses which require corrosion resistance.

In the resin having hydroxyl group to be employed in the presentinvention, content of hydroxyl group is preferably not less than 10 as ahydroxyl value and, in the case that the hydroxyl value is less than 10,vinyl groups are not sufficiently introduced, and it becomes difficultto copolymerize with a variety of polymerizable monomers including thepolymerizable monomers having carboxylic group, resulting in that awater dispersion property often lowers.

Further, there becomes insufficient a reaction with the polyisocyanatecompound (V-B) (a hydrophobic csosslinking agent) and, as a result, asufficient corrosion resistance cannot be obtained by a decline ofcrosslinking degree.

On the other hand, although the copolymer which becomes a hydrophobicportion may even contain acidic components, in the case, an acid valueis desirably not more than 10. In the case containing more than 10 ofsuch the acidic components, a hydrophilic property is unavoidablyelevated and a core-shell structure is destroyed, resulting in thatstability lowers after introduction of a hydrophobic crosslinking agent.

Further, in the acrylic polyol resin (VI-A) to be employed in thepresent invention, a number average molecular weight appropriatelyranges in 3,000-100,000. It preferably ranges in 3,000-50,000. In thecase that the number average molecular weight is less than 3,000, sinceit becomes impossible to stably introduce the polyisocyanate compound(V-B) (a hydrophobic crosslinking agent) into the particles and,further, since there are not occasionally obtained physical propertiesin a coating layer such as sufficient water resistance and outerappearance of a coating layer, it is not preferred.

On the other hand, in the case that the number average molecular weightis more than 100,000, gelation is unavoidably caused, otherwise,viscosity largely increases during emulsifying by a phase inversion,resulting in that it unpreferably becomes difficult to produce anexcellent water-dispersion.

Further, it is also required that content of the vinyl-based monomershaving carboxylic group which becomes a hydrophilic segment is at least10 of an acid value as a minimum limit for self-emulsifying of a resin.

Herein, although carboxylic group is employed as the hydrophilicsegment, since a sufficient hydrophilic property is not shown in thecase of a state of a carboxylic acid, usually, it is preferred that thehydrophilic property is increased by a change to an amine salt.

Even in the case that the content of carboxylic group is of a largeamount, if a carboxylic acid salt neutralized by an amine salt is of asmall amount, a resin does not manifest a self-emulsifying property.That is, if a neutralization ratio by the amine salt is excessivelyhigh, even in the case that it becomes water-soluble, awater-dispersible resin becomes obtained by decreasing theneutralization ratio. However, even though 100% of carboxylic groupscontained in view of composition are neutralized, it should be designedso that it does not become water-soluble.

Further, since the carboxylic group itself is high in polarity, in thecase that the content exceeds 60% by weight, it is not preferred becauseof adversely affecting to corrosion resistance.

As content of the hydroxyalkyl(meth)acrylate composition modified by asmall amount of lactones of the present invention, it requires not lessthan 10 as a hydroxyl value in the vinyl-based copolymer obtained inconsideration of a reaction with the crosslinking agent.

However, in the case of a resin in which the content of thehydroxyakyl(meth)acrylate composition modified by a small amount oflactones of the present invention exceeds 300 as a hydroxyl value, suchthe content is not preferred because of adversely affecting to acorrosion resistance.

The acrylic polyol resin (VI-A) in relation to the present invention maybe even a vinyl-based copolymer having carboxylic groups andcrosslinkable functional groups which is obtained by allowing to react aresin having hydroxyl groups obtained by polymerization of thehydroxyakyl(meth)acrylate composition modified by a small amount oflactones with (meth)acrylic anhydride, and then allowing to react areaction product obtained with the above-described vinyl-based monomerhaving carboxylic group and the above-described other vinyl-basedmonomers.

Further, the acrylic polyol resin (VI-A) in relation to the presentinvention may be even a resin having hydroxyl groups obtained by usingthe above-described resin having hydroxyl groups and at least one ofresins selected from the group consisting of the above-described resinhaving hydroxyl groups, urethane resin having hydroxyl groups, epoxyresin having hydroxyl groups, cellulose derivative having hydroxylgroups, and polyester resin having hydroxyl groups.

In the case, as the resin having hydroxyl groups, there should beemployed a hydrophobic resin not having a self-water dispersibleproperty. Vinyl group can be readily introduced by allowing to reactsuch the hydrophobic resin not having a self-water dispersible propertywith a specified acid anhydride such as (meth)acrylic anhydride.

The kind of copolymers form core-shell structure type particles in whicha hydrophobic portion and hydrophilic portion are differently separatedfrom each other. For that reason, there can be formed crosslinkedparticles which are particularly excellent in a dispersion stabilityafter introduction of the polyisocyanate compound (V-B) (a hydrophobiccrosslinking agent).

Further, such the copolymers cannot be modified to a water-soluble resinbecause of forming a core-shell structure after emulsifying by a phaseinversion in spite of a high neutralization ratio in carboxylic groups.In other words, it may safety be said that it is a resin which isexcellent in capability of accepting a hydrophobic substance such as thehydrophobic crosslinking agent.

Still further, such the resin having hydroxyl groups can be alsoemployed together with a condensation-based resin without being limitedto a radical polymerization-based resin.

It has a merit of capability of selecting an appropriate resin accordingto various grade of corrosion resistance to be desired or various usesand capability of employing together. In addition, it may safety be saidthat there has been certainly conventionally nothing in a method forreadily preparing the crosslinked particles using a variety of thecondensation-based resins.

By using the crosslinked particles having such a novel structure, forthe first time, there can become provided a novel and useful coatingwhich is excellent in corrosion resistance

Incidentally, glycidyl groups can be also allowed to copolymerize withthe resin having hydroxyl group. Such the glycidyl groups are containedin the core portion of a particle after emulsifying by a phase inversionand, whereby, the groups are isolated from carboxylic groups containedin adjacent particles and, as described above, in the case that glycidylgroups are allowed to copolymerize with the vinyl-based resin havinghydroxyl group, there can be obtained exceedingly good crosslinkedparticles which are excellent in a dispersion stability (in more detail,gelation is not caused after a time lapse).

Glycidyl groups act in order to elevate a crosslinking degree bypartially reacting with the carboxylic groups contained in thepolyisocyanate compound (V-B) (a hydrophobic crosslinking agent) or in acopolymer which forms the core portion after formation of particles.

Further, the glycidyl groups remained in the core portion act also asfunctional group for self-crosslinking in the crosslinked particlesthemselves during baking.

In a water-based coating, a high molecular weight type epoxy resin canbe simultaneously employed and, if such a method is applied, there canbe also employed a low molecular weight epoxy resin such as “Epikote1001” [a product by Dainippon Ink Kagaku Kogyo, Ltd.], provided that itis desirably employed in a field in which weatherability is notrequired.

As the aromatic epoxy resins to be employed, for example, there areenumerated a bisphenol A type epoxy resin, a bisphenol F type epoxyresin, and a novolak type epoxy resin, etc.

Of the epoxy resins, there is desired an epoxy resin having an epoxyequivalent of not less than 400, and there is also preferably employedan epoxy resin having an epoxy equivalent of not less than 4,000.

As an epoxy resin having an epoxy equivalent of 400-4,000, for example,there are enumerated “Epikote 1001, 1004, 1007 or 1009” manufactured byShell, A.G. in Netherlands, or “Epichlone 4055, 7055, and 9055”manufactured by Dainippon Ink Kagaku Kogyo, Ltd., etc.

Further, as an epoxy resin having an epoxy equivalent of not less than4,000, for example, there are enumerated “Epikote 1010 or 1100L”manufactured by Shell, A.G., or “PKHA”, “PKHC”, “PKHH”, or “PKHJ” whichare a phenoxy resin manufactured by Union Carbide, Co. in USA.

Still further, as the epoxy resin, in addition to the above-describedones, there can be also employed a variety of modified epoxy resins suchas a fatty acid-modified epoxy resin, a phenol-based compound-modifiedepoxy resin, or an alcohol-based compound-modified epoxy resin.

As the fatty acids to be employed for modifying, there are enumerated avariety of vegetable oil fatty acids such as a soybean oil fatty acid ora castor oil fatty acid; a variety of organic acids such as benzoic acidor acetic acid and, as the phenol-based compound, there are enumeratedbisphenol A, phenol, and cresol, etc. and, further, as the alcohol-basedcompound, there are enumerated methanol, butanol, or benzyl alcohol,etc. By heating these modifiers with aromatic-based epoxy resin at100-170° C. or so under the absence or the presence of appropriatereaction catalysts such as a tertiary amine or a quaternary amine, theabove-described epoxy resins are obtained.

It is needless to say that there can be employed solely the respectivegroups of epoxy resins or a plurality of epoxy resins in the respectivegroups, or there can be (simultaneously) employed a plurality of epoxyresins between the respective groups.

Further, cellulose derivatives having hydroxyl groups can be alsosimultaneously employed. Such the cellulose derivatives are a resinsystem which is excellent in, particularly, oil resistance and solventresistance, and there are obtained crosslinked particles which aredifferent in characteristics from the above-described vinyl-based resinhaving hydroxyl group in such a viewpoint.

However, in the case that the cellulose derivatives are employed in awater-based coating, since hydrolysis resistance and thermally-yellowingresistance are low and uses are occasionally limited, it must be paidattention to.

As the cellulose derivatives having hydroxyl groups, there is typicallyenumerated, for example, an ester-modified cellulose derivatives havinghydroxyl groups or an ether-modified cellulose derivatives havinghydroxyl groups, which is usually for a coating.

First, if there are typically exemplified only the ester-modifiedcellulose derivatives having hydroxyl groups, there are enumerated anitrocellulose, a cellulose acetate-butylate, a celluloseacetate-propionate, a cellulose acetate-phthalate, an acetyl cellulose,a cellulose propionate, a cellulose butylate, a cellulose phosphate, anda cellulose sulphate, etc.

Further, if there are typically exemplified only the ether-modifiedcellulose derivatives having hydroxyl groups, there are enumerated amethyl cellulose, an ethyl cellulose, a butyl cellulose, a benzylcellulose, a carboxymethyl cellulose, a carboxyethyl cellulose, anaminoethyl cellulose, an oxyethyl cellulose, a hydroxyethyl cellulose, ahydroxypropyl cellulose, and a hydroxypropyl methyl cellulose, etc.

Of the cellulose derivatives having hydroxyl groups, there isparticularly desired the use of the cellulose acetate-butylate(hereinafter, it is referred to as CAB) obtained by furtherbutyl-esterifying a partially acetylated cellulose.

In the cellulose derivatives having hydroxyl groups to be employed inthe present invention, a number average molecular weight preferablyranges in 3,000-300,000, and more preferably in 5,000-150,000.

Further, in the cellulose derivatives having hydroxyl groups, content ofhydroxyl groups is desirably not less than 0.4% by weight. In the casethat the content of hydroxyl groups is less than 0.4% by weight, agrafting ratio lowers because (meth)acryloyl groups becomes unavoidablyslight which are introduced into the cellulose derivatives havinghydroxyl groups, unpreferably resulting in that the modified polymerhaving carboxylic groups is not apt to be self-emulsified.

If there are typically exemplified only the cellulose derivatives havinghydroxyl groups as commercially supplied products, there are enumerated“CAB” series, “CAP” series, and “CA” series which are manufactured byEastman Kodak, Ltd. in USA.

Further, a urethane resin having hydroxyl groups can be alsosimultaneously employed. By the use of the urethane resin, there can beobtained characteristics such as elasticity and flexibility derived fromthe urethane resin, and there can become obtained a coating layer havinga corrosion resistance which is tough in impact.

Such the polyurethane resin having hydroxyl groups is obtained byallowing to polymerize an aliphatic and/or cycloaliphatic diisocyanatewith an alkyl diol, a polyether diol, a polyester diol, or a mixturethereof and, optionally, a low molecular weight polyhydroxy compoundunder the presence or absence of an organic solvent not containing anactive hydrogen atom (an active hydrogen group) in the molecule in aproportion of OH/NCO equivalent ratio ranging in 1.1-1.9 by a one-shotmethod or a multi-stage method.

Herein, in the case that the OH/NCO equivalent ratio is less than 1.1,hydroxyl value becomes unavoidably small, resulting in that introductionof vinyl group is apt to become insufficient and, as a result therefrom,copolymerization with a monomer having carboxylic group described lateris apt to become insufficient and, as a result, a water dispersionproperty often lowers.

On the other hand, in the case of exceeding 1.9, products having lowmolecular weight are unavoidably produced, and there become unpreferablyobserved various characteristics such as physical properties in acoating layer.

As the above-described aliphatic and cycloaliphatic diisocyanate to beemployed for the preparation of such the polyurethane resin havinghydroxyl groups, particularly, there are typically enumerated aliphaticdiisocyanates having a carbon number of 2-12 such as hexamethylenediisocyanate, 2,2,4-trimethylhexane diisocyanate, or ridinediisocyanate,and particularly, there are typically enumerated cycloaliphaticdiisocyanates having a carbon number of 4-18 such as 1,4-cyclohexanediisocyanate, 1-isocyanate-3-isocyanatemethyl-3,5,5-trimethylcyclohexane(isophorone diisocyanate), 4,4′-dicyclohexylmethane diisocyanate,methylcyclohexylene diisocyanate, and isopropylidenedicyclohexyl-4,4′-diisocyanate.

Further, there can be enumerated a modified product (carbodiimide,urethodion or urethoimine-contained modified product) of the variousdiisocyanates, or a mixture of two or more kinds.

Of those, as a preferred one, there are enumerated the cycloaliphaticdiisocyanates, particularly, 1,4-cyclohexane diisocyanate,1-isocyanate-3-isocyanatemethyl-3,5,5-trimethylcyclohexane or4,4′-dicyclohexylmethane diisocyanate.

Herein, in the case that an aromatic diisocyanate is employed, a coatinglayer is apt to yellow in curing for baking and, since the coating layeris apt to discolor by an influence of an ultraviolet ray, there must bepaid attention according to uses.

As the polyetherdiol, there are particularly exemplified typicalexamples alone, and there are enumerated a variety of alkylene oxidessuch as ethyleneoxide, propylene oxide, or butylene oxide; a compoundobtained by polymerization or copolymerization of a variety ofheterocyclic ethers such as tetrahydrofuran; or a polyethylene glycol, apolypropylene glycol, a polyethylene-polypropylene glycol, apolytetramethylene etherglycol, and a polyhexamethylene etherglycol,etc.

As the polyesterdiol, there are particularly exemplified typicalexamples alone, and there are enumerated compounds such as apolyethylene adipate, a polybutylene adipate, a polyhexamethyleneadipate, a polyneopentyl adipate, a poly-3-methylpentyl adipate, apolyethylene/polybutylene adipate, a polyneopentyl/hexyl adipate whichare obtained by polycondensation of dicarboxylic acids typified byadipic acid, succinic acid, sebasic acid, maleic acid, fumaric acid, andphthalic acid with glycols typified by ethylene glycol, propyleneglycol, 1,4-butane diol, 1,6-hexane diol, 3-methyl-1,5-pentane diol,neopentyl glycol, bishydroxymethyl cyclohexane; or polylactone diolstypified by a polycaprolactone diol, a poly-3-methyl-valerolactone diol;polycaprbonate diols; or a mixture of two or more kinds thereof, etc.

As the alkyldiol, there are particularly exemplified typical examplesalone, and there are enumerated fatty acid esters of glycerine.

Further, as polyhydroxy compounds having a low molecular weight, thereare particularly exemplified typical examples alone, and there areenumerated glycols having a number average molecular weight of less than500 which are enumerated as raw materials for the polyester diols oradducts (a molecular weight of less than 500) in which a small amount ofan alkylene oxide is added to the glycols; a variety of trivalentalcohols such as glycerine or trimethylol propane, or adducts (amolecular weight of less than 500) in which a small amount of analkylene oxide is added to the trivalent alcohols; and a mixture of twoor more kinds thereof, etc.

Amount of the polyhydroxy compounds having a low molecular weightappropriately ranges in usually 0.1-20% by weight, and preferably0.5-10% by weight with respect to the above-described polyether diols orpolyester diols.

Further, as polyether diols and/or polyester diols to be employed forthe preparation of the above-described urethane resins, there areemployed ones having a number average molecular weight of 500-5,000, andpreferably 1,000-3,000.

In the case that the number average molecular weight is less than 500,the urethane resins unavoidably becomes rigid, resulting in that desiredproperties are not obtained in a coating layer and, on the other hand,in the case of excessively exceeding 5,000, a molecular weight in theurethane resins obtained also becomes high and, as a result, a hydroxylvalue lowers, resulting in that a modification by a vinyl becomesinsufficient.

Further, as described later, it is needless to say that carboxylicgroups may be introduced for the purpose of elevating compatibility witha copolymer from a variety of polymerizable monomers including a varietyof carboxylic group-contained polymerizable monomers, and adhesion to abody to be covered (a body to be coated). Specifically, for example, itis introduced by allowing to react a variety of dimethylol alkane acidssuch as dimethylol propionic acid.

However, the introduction of hydrophilic groups such as carboxylicgroups elevates a hydrophilicity in the urethane resins and, as a resulttherefrom, since water resistance is lowered in a coating layer,addition amount is preferably limited to not more than 5% by weight.

Likewise, although the polyester-based resin can be also employedtogether as a resin having hydroxyl groups, a small molecular weightcauses a problem of hydrolysis resistance in the case of a water-basedcoating. On the other hand, since a large molecular weight occasionallycauses an insufficient modification and an amount of crosslinkablefunctional groups becomes insufficient, crosslinking density cannot beelevated. For that reason, there is observed a tendency of poor solventresistance.

As described hereinabove, a variety of resins having hydroxyl groups areallowed to react with (meth)acrylic anhydride in an inert organicsolvent under the absence of catalysts and, moreover, at a relativelylow temperature of 60-80° C. for 1-6 hours or so while agitating tointroduce vinyl groups in to the resins.

A reaction (esterification) in the case is conducted by monitoring with,for example, a Fourier transformation ultraviolet ray photometer (FI-IR)until an absorption by a specified acid anhydride such as (meth)acrylicanhydride is not observed or maintained at a low constant value,whereby, completion of the reaction can be confirmed through such meansor methods. It is to be noted that a confirmation means is not limitedthereto alone.

In the present invention, as the inert organic solvent to be employed insynthesis of the resin having hydroxyl groups and the reaction with ananhydride, there are particularly exemplified typical examples alone,and there are enumerated a variety of ketones such as acetone,methylethyl ketone, methylisobutyl ketone, ethylpropyl ketone, andethylbutyl ketone; esters; or aromatic hydrocarbons, etc., and those arepreferably employed.

The (meth)acrylic anhydrides are allowed to react in a proportion of anamount to be modified by the (meth)acrylic anhydrides of 0.5-30% withrespect to hydroxyl group equivalent contained in 100 g of the resinhaving hydroxyl groups. In the case that the amount to be modified isless than 0.5%, vinyl groups are not sufficiently introduced, resultingin that copolymerization with monomers, which is successively conducted,is not sufficiently conducted and a water dispersion property lowers.

On the other hand, in the case of exceeding 30%, those arehighly-polymerized by successive copolymerization, and gelation isunpreferably apt to be caused.

By allowing to react the vinyl group-modified resin having hydroxylgroups obtained herein with a variety of vinyl-based monomers includinga carboxylic group-contained vinyl-based monomer as an essentialcomponent, the acrylic polyol resin (VI-A) is obtained which is adesired product.

Incidentally, in the case of obtaining the acrylic polyol resin (VI-A),there can be also blended two or more kinds of the vinyl group-modifiedresin having hydroxyl groups.

For example, in the resin having hydroxyl groups, a crosslinking densitycan be also controlled by blending a copolymer having glycidyl groupswith a copolymer not having glycidyl groups obtained by homopolymerizingor copolymerizing the hydroxyakyl(meth)acrylate composition modified bya small amount of lactones in relation to the present invention.

In the case, since a crosslinking agent and glycidyl groups form acrosslinked structure like an IPN (Interpenetrating polymer network),respectively, there is shown a more excellent corrosion resistance.

Further, by blending the resin having hydroxyl groups with the urethaneresin having hydroxyl groups, there can be also conveniently achievedflexibility in a urethane resin and preparation of a vinyl-basedpolymer.

In the case, even in different kind of resins themselves, since thoseare partially connected by chemical bonds through simultaneouslycopolymerizing those, compatibility becomes excellent, and clouding,etc. in a coating layer is not apt to be caused.

As polymerizable monomers to be (co)polymerized with the vinylgroup-modified resins having hydroxyl groups, there are basicallyemployed monomers containing at least 10% by weight of the vinyl-basedmonomer having carboxylic group in total polymerizable monomers. In thecase that use amount of the vinyl-based monomer having carboxylic groupis less than 10% by weight, there is unpreferably observed a tendencythat dispersion stability of a resin becomes unavoidably worse in awater-based medium.

For example, as the vinyl-based monomer having carboxylic group andother vinyl-based monomers, the above-mentioned ones are enumerated.Incidentally, as a reaction ratio of the vinyl group-modified resinshaving hydroxyl groups with respect to a variety of the vinyl-basedmonomers having carboxylic group, ratio of the former resins:lattermonomers appropriately ranges in 20:80-90:10 by weight ratio.

In the case that the use ratio of the vinyl-modified resins havinghydroxyl groups is less than 20% by weight, since there is occasionallyobserved a case that a variety of properties in a resin are notunavoidably made the most, it is not preferred and, on the other hand,in the case that the use ratio of the resins is more than 90% by weight,the number of carboxylic groups becomes small, and a self-dispersionproperty becomes insufficient in a resin obtained, unpreferablyresulting in that dispersing becomes often impossible in a water-basedmedium.

There is conducted a polymerization reaction of a variety of thevinyl-based monomers including the carboxylic group-containedvinyl-based monomer with the vinyl-modified resins having hydroxylgroups using a variety of radical polymerization initiators such asazobisisobutyronitrile or benzoyl peroxide which are publicly-known at atemperature of 60-150° C. or so in an inert organic solvent.

As the organic solvent in the case of conducting the reaction, there areparticularly exemplified typical examples alone, there are enumerated avariety of ketones such as acetone, methylethyl ketone, and diisobutylketone; or aromatic hydrocarbons such as toluene or xylene. Further,there can be also preferably employed a variety of ester-based solventssuch as ethyl acetate or butyl acetate.

In a method for the preparation of crosslinked particles in the presentinvention, a variety of the acrylic polyols (VI-A) (a self-dispersiblecrosslinking agent) as described hereinabove are mixed with thepoyisocyanate compound (VI-B) (a hydrophobic crosslinking agent), andthen, emulsified by phase inversion into a water-based medium to involvethe hydrophobic crosslinking agent in the particles, followed byaccelerating crosslinking in the particles, whereby, desired crosslinkedparticles can be obtained.

As the poyisocyanate compound (VI-B) to be employed in the presentinvention, there are aromatic, aliphatic, and cycloaliphaticpolyisocyanates and, as the aromatic polyisocyanates, there arepreferred polyisocyanates having a carbon number of 6-30, as thealiphatic polyisocyanates, there are preferred polyisocyanates having acarbon number of 4-30, and as the cycloaliphatic polyisocyanates, thereare preferred polyisocyanates having a carbon number of 8-30. Forexample, there are enumerated 2,4-naphthalene diisocyanate,1,5-naphthalene diisocyanate, 4,4′-diphenylmethane diisocyanate,4,4′-diphenyldimethylmethane diisocyanate, dialkyldiphenylmethanediisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,4′-diphenylenediisocyanate, 4,4′-dibenzyl diisocyanate, 1,3-phenylene diisocyanate,1,4-phenylene diisocyanate, tolylene diisocyanate such as 2,4-tolylenediisocyanate and, 2,6-tolylene diisocyanate, xylilene diisocyanate suchas p-xylilene diisocyanate and m-xylilene diisocyanate,1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate,1,6-hexamethylene diisocyanate,2,2,4-trimethylhexamethylene-1,6-diisocyanate,2,4,4-trimethylhexamethylene-1,6-diisocyanate, ridine diisocyanate,cyclohexane-1,4-diisocyanate, isophorone diisocyanate, 4,4′-diisocyanatedicyclohexane, dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexanediisocyanate such as 1,3-bis(isocyanatemethyl)cyclohexane andmethylcyclohexane-2,4 (or 2,6)-diisocyanate, or an adduct of thesediisocyanates to a polyvalent alcohol such as ethylene glycol, propyleneglycol, a polyethylene glycol, a polypropylene glycol, apolycaprolactone polyol, trimethylol ethane, and trimethylol propane, apolyester resin (including an oil-modified type) having a functionalgroup which reacts with isocyanate group, an acrylic resin, etc., andwater, etc., a buret compound, a polymer allowed to react betweenisocyanates, or an equimolar adduct of 2-hydroxypropyl(meth)acrylate-hexamethylene diisocyanate, a copolymer essentiallycontaining a vinyl-based monomer which has an isocyanurate group such asisocyanatemethyl (meth)acrylate and a copolymerizable unsaturated group,or compounds described in JP-A-61072013 Official Gazette, and a blockedcompound blocked by a blocking agent such as a lower monovalent alcohol,phenols, methylethylketoxime, and a lactam, etc.

The diisocyanates may be employed solely or even in combination of towor more kinds.

From a viewpoint of a color tone in a coating layer obtained using thecurable resin composition of the present invention, as a polyisocyanatecompound, non-yellowing type polyisocyanates are preferred, and thefollowing ones are disclosed as an example.

There are enumerated aliphatic-based polyisocyanates such as1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate,1,6-hexamethylene diisocyanate,2,2,4-trimethyl-1,6-hexamethylenediisocyanate, and ridine diisocyanate;cycloaliphatic-based polyisocyanates such as isophorone diisocyanate,methyl cyclohexane-2,4-(or 2,6) diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and 1,3-bis(isocyanatemethyl) cyclohexane,and the above-described derivatives (including an adduct) therefrom. Ofthose, there are preferably enumerated 1,6-hexamethylene diisocyanate(hereinafter, abbreviated as HMDI), isophorone diisocyanate(hereinafter, abbreviated as IPDI), and a derivative (including anadduct) therefrom in view of weatherability and an ease ofindustrially-obtaining.

Since the polyisocyanate compounds reacts with polyols in a basematerial even at room temperatures, those include a problem that thoseare poor in storage stability, and handling is troublesome and, thoseare unpreferred in view of safeness and hygiene. Accordingly, blockedtype polyisocyanates are preferred as the polyisocyanate compounds.

Although the blocked type polyisocyanates (hereinafter, occasionallyreferred to as a highly-branched block polyisocyanate) are obtained evenonly by allowing to react the polyisocyanates with a polyvalent alcohol,more preferably, those can be obtained by cyclic trimerization of anisocyanate, that is, isocyanuration after allowing to react adiisocyanates with the polyvalent alcohol.

As the polyvalent alcohol in the case, there is preferred an alcoholhaving three or more functionalities and, as a polyvalent alcohol havinga low molecular weight, for example, there are trimethylol propane,glycerine, 1,1,7-trimethylol heptane, 1,2,7-trimethylol heptane, andpentaerythritol, etc. As a polyvalent alcohol having a higher molecularweight, for example, there are enumerated aliphatic hydrocarbon polyols,polyether polyols, polyester polyols, and epoxy resins haing a pluralityof hydroxyl groups at terminals, etc.

As the aliphatic hydrocarbon polyols, for example, there are enumerateda polybutadiene having hydroxyl group at terminals and a hydrogenateproduct therefrom, etc. Further, as the polyether polyols, for example,there are enumerated so-called polymer polyols, etc. that is, polyetherpolyols or polytetramethyleneglycols obtained by adding alkylene oxidessuch as ethylene oxide or propylene oxide alone or in a mixture, andcomponents obtained by obtained by polymerizing acrylic amides in mediawhich are polyethers obtained by reacting alkylene oxides withpolyfunctional compounds such as ethylenediamine or ethanolamines.

As the polyester polyols, there are enumerated polyester polyol resinsobtained by condensation reaction of at least one of a polybasic acidwith at least one of polyvalent alcohols and polycaprolactones obtainedby ring-opening polymerization of ε-caprolactone using the polyvalentalcohols.

As the polybasic acid, for example, there are enumerated phthalic acid(anhydride), terephthalic acid, isophthalic acid, tetrahydrophthalicacid (anhydride), hexahydrophthalic acid (anhydride),4-methylhexahydrophthalic acid (anhydride), 3-methylhexahydrophthalicacid (anhydride), 3-methyltetrahydrophthalic acid (anhydride),trimerritic acid (anhydride), pyromerritic acid (anhydride), het acid(anhydride), hymic acid (anhydride), adipic acid, sebasic acid, azelaicacid, succinic acid (anhydride), maleic anhydride, fumaric acid,itaconic acid, and a dimer acid, etc. The acid may be employed even inthe form of an ester of a lower alcohol such as dimethylisophthalate anddimethylterephthalate.

The polyvalent alcohols are a compound having at least two alcoholic orphenolic hydroxyl groups in a molecule, for example, there arespecifically enumerated ethylene glycol, diethylene glycol,triethyleneglycol, polyethylene glycol, 1,6-hexanediol, pentanediol,cyclohexane dimethanol, propylene glycol, butylene glycol, butylenediglycol, trimethylol ethane, trimethylol propane, glycerine, neopentylglycol, sorbitol, tris(2-hydroxyethyl)isocyanurate, diethanol amine,diisopropanol amine, bisphenol A, and bisphenol F, etc.

As the epoxy resins, for example, there are enumerated a novolak type,β-methylepichlorohydrin type, a cyclic oxirane type, a glycidylethertype, a glycolether type, an epoxy type of an aliphatic unsaturatedcompound, an epoxidized fatty acid ester type, a polycarboxylic acidester type, an aminoglycidyl type, a halogenated type, and resorcinoltype, etc.

Of the polyols, there are preferably employed the above-describedpolyvalent alcohol having a low molecular weight and a polyether polyolhaving 3-8 pieces of hydroxyl groups in a molecule, the aliphatichydrocarbon polyols, and polyester polyols and, particularly preferably,the polyester polyols. These may be employed solely or in combination oftwo or more kinds. Aliphatic or cycloaliphatic diisocyanate and thepolyvalent alcohols are allowed to react at 50-200° C., and preferably50-150° C. In the case, solvents may be employed, and there arepreferably employed solvents which are inactive to an isocyanate. Assuch the inactive organic solvents, for example, there are employed atleast one kind of aliphatic hydrocarbons such as hexane, heptane, andoctane, aromatic hydrocarbons such as benzene, toluene, and xylene,esters, and ketones. Since the solvents occasionally contain moisture,it is preferred to optionally remove the moisture. Although the reactioncan be conducted even after an isocyanuration reaction, it is preferablyconducted prior to the isocyanuration reaction.

In the isocyanuration reaction, catalysts are usually employed. Thecatalysts to be employed herein are preferably basic, for example, thereare employed a quaternary ammonium salts and a weak organic acid saltthereof, an alkyl metal salt of an alkyl carboxylic acid, an metalalcholate, and a compound having an aminosilyl group, etc. Concentrationof the catalysts is usually selected from a range of 210 ppm to 1.0%based on isocyanate compounds.

In the reaction, solvents may be employed or even not employed. In thecase that the solvents are employed, there should be employed solventswhich are inert to an isocyanate group.

Reaction temperature is usually 20-160° C., and preferably 40-130° C.Termination point of the reaction depends upon the kind of thepolyvalent alcohols to be employed, and it is a period at which yieldattains to approximately 30%. When the reaction attains to a targetyield, for example, the reaction is terminated by deactivation of thecatalysts by, for example, sulphonic acid, phosphoric acid, andphosphates, etc.

In a highly-branched polyisocyanate having an isocyanurate structureafter removal of unreacted diisocyanates and solvents, viscosity at 25°C. is preferably 0.5-300 Pas. In the case that the viscosity exceeds 300Pas, outer appearance in a coating layer is adversely affectedoccasionally and, in the case of being less than 0.5 Pas, it isdifficult to obtain a range of an average functional group number of thepolyisocyanate regulated in the present invention.

As a blocking agent for obtaining the highly-branched blockpolyisocyanate, for example, there are enumerated phenol-based ones suchas phenol, cresol, xylenol, ethylphenol, o-isopropylphenol, butylphenolsuch as p-tert-butylphenol, p-tert-octylphenol, nonylphenol,dinonylphenol, styrenized phenol, oxybenzoic acid phenol, thymol,p-naphthol, p-nitrophenol, p-chlorophenol; alcohol-based ones such asmethanol, ethanol, propanol, butanol, ethyleneglycol, methylcellosolve,butylcellosolve, methylcarbitol, benzyl alcohol, phenylcellosolve,fulfurylalcohol, and cyclohexanol; active methylene-based ones such asdimethyl maloate, diethyl maloate, methylacetoacetate,ethylacetoacetate, and acetyl acetone; mercaptan-based ones such asbutyl mercaptan, thiophenol, and tert-dodecyl mercaptan; amine-basedones such as diphenyl amine, phenylnaphtyl amine, aniline, andcarbazole; acid amide-based ones such as acetanilide, acetoanisidide,amide acetate, and benzamide; lactam-based ones such as ε-caprolactam,δ-valerolactam, γ-butyrolactam, and β-propiolactam; acid imide-basedones such as succinic acid imide and maleic acid imide; imidazole basedones such as imidazole, 2-methylimidazole, and 2-ethylimidazole;urea-based ones such as urea, thiourea, an ethylene urea; carbamide acidsalt-based ones such as N-phenylcarbamic acid phenyl and 2-oxazolidone;imine-based ones such as ethyleneimine and a polyethylene imine;oxime-based ones such as formaldoxime, acetoaldoxime, acetoxime,methylethylketoxime, methylisobutylketoxime, and cyclohexanoeoxime;bisulphite-based ones such as sodium bisulphite and potassiumbisulphite, etc., and these may be even as a mixture.

Of those, there are preferred the phenol-based ones, lactam-based ones,alcohol-based ones, and oxime-based ones and, there are particularlypreferred nonylphenol, styrenized phenol, oxybenzoic acid ester,acetoxime, methylethylketoxime, and ε-caprolactam.

In the case that a low temperature (not more than 140° C.) baking isdemanded, particularly, an oxime-based blocking agent is most preferred.

By allowing to react the blocking agent with the highly-branchedpolyisocyanate, the highly-branched blocked polyisocyanate can beobtained. Reaction of the isocyanate with the blocking agent can beconducted regardless of the presence or absence of solvents. In the casethat the solvents are employed, there should be employed solvents whichare inert to an isocyanate group.

In the reaction for blocking, there may be even employed catalysts suchas organic salts of metals such as tin, zinc, lead, and a tertiaryamine, etc. The reaction can be conducted at −20 to 150° C. and,preferably, 0 to 100° C. In the case of exceeding 100° C., sidereactions are possibly caused and, on the other hand, in the case of toolow temperatures, reaction rate becomes slow, and it is disadvantageous.

The block polyisocyanate to be employed in the present invention has thenumber of average functional group of 4.5-10, preferably, 5-8 per 1molecule of the block polyisocyanate.

The number of average functional group in the block polyisocyanate is anumber of an isocyanate functional group to be statistically possessedin 1 molecule of the block polyisocyanate, and it is calculated by theabove-described equation (1) from a number average molecular weight ofthe polyisocyanate before the blocking reaction and an isocyanateconcentration (%).

As the above-described polyisocyanate compound to be employed as thehydrophobic crosslinked particles, there are typically enumerated avariety of toluene diisocyanate(TDI)-based polyisocyanates typified by atrimethylolpropane (TMP) adduct-prepolymer; a variety of hexamethylenediisocyanate(HMDI)-based polyisocyanates typified by a TMPadduct-prepolymer; (HMDI)-based polyisocyanates which are buret typeHMDI-based polyisocyanates or an isocyanurate-prepolymer; isophoronediisocyanate(IPDI)-based prepolymers which are anisocyanurate-prepolymer; a variety of xylilene diisocyanate (XDI)-basedpolyisocyanates typified by a TMP adduct-prepolymer; or4,4′-diphenylmethane (MDI)-based diisocyanates, etc.

In the above-described hydrophobic crosslinked particles, an epoxy resincan be simultaneously employed. Particularly, typical resins alone areexemplified, and there are enumerated “Epikote 828 or 1001” which is abisphenol A type one manufactured by Yuka Shell, Ltd.; an epoxidizedpolybutadiene manufactured by Adeka Argus, Ltd.; “DEN431, 438, XD-7818,XD-7855, or DER331” which is a phenol-novolak type epoxy resinmanufactured by Dow Chemical, Ltd.; “ECN268, 273, 280, 285, or 299”which is a cresol-novolak type epoxy resin manufactured by Asahi KaseiKogyo, Ltd.; or multifunctional glycidyl amines or multifunctionalglycidyl ethers, etc.

Further, as such the epoxy resins, there can be also employed copolymershaving glycidyl groups obtained by copolymerization ofglycidyl(meth)acrylate.

In the present invention, since urethane bonds produced by using thepolyisocyanate compound can exhibit more excellent properties such as,above all, chemical resistance and hydrolysis resistance compared toother ether bonds and ester bonds, a mode of the present invention isparticularly desired.

The acrylic polyol resin (VI-A) and the polyisocyanate compound (VI-B)in relation to the present invention construct an essential component inthe curable resin composition of the present invention, and it isemployed as raw materials for a coating.

There is decided an equivalent ratio of isocyanate groups or a blockedisocyanate group in the polyisocyanate with respect to hydroxyl groupsin the resin having hydroxyl groups according to physical properties ina coating layer to be required.

The acrylic polyol resin (VI-A) obtained by using thehydroxyakyl(meth)acrylate composition modified by a small amount oflactones and the polyisocyanate compound (VI-B) are preferablyformulated in a ratio of OH/NCO=1/0.5-1/1.5 (equivalent ratio) from aviewpoint of characteristics in a coating layer. Above all, those areformulated in a range of OH/NCO=1/0.7-1/1.2 (equivalent ratio).

In the case that NCO is not more than 0.5 equivalent with respect to 1equivalent of OH, there are not shown physical properties to be desiredfor a coating layer such as extensibility, weatherability, solventresistance, and staining resistance and, in the case of not less than1.5 equivalent, although the physical properties for a coating layer areobtained, it is not preferred from a viewpoint of readily bubbling undera high temperature, and a high price in a coating.

The curable resin composition of the present invention contains 20-90parts by weight of the acrylic polyol resin (VI-A) obtained by using thehydroxyakyl(meth)acrylate composition modified by a small amount oflactones (a) and 5-50 parts by weight of the polyisocyanate compound(VI-B) as essential components, provided that total of the (VI-A) and(VI-B) does not exceed 100 parts by weight.

In the case that the acrylic polyol resin (VI-A) is less than 20 partsby weight, there lacks an amount of a hydrophilic portion taking chargeof a water dispersibility, and there lowers a water dispersion stabilityand, in the case of exceeding 90 parts by weight, there becomeunpreferably worse workability and a water dispersibility. In the casethat the polyisocyanate compound (VI-B) is less than 5 parts by weight,curability becomes insufficient and, on the other hand, in the case ofexceeding 50 parts by weight, a cured coating layer becomes unpreferablytoo rigid or too brittle.

As use ratio of the acrylic polyol resin (VI-A) with respect to thepolyisocyanate compounds (VI-C), the polyisocyanate compounds (VI-B) are60-10% by weight with respect to the 40-90% by weight of the acrylicpolyol resin (VI-A). In the case that the use ratio the acrylic polyolresin (VI-A) is less than 40% by weight, a self-condensation reactionincreases in the polyisocyanate compounds themselves, and coating layerbecomes brittle, resulting in becoming not appropriate as a coating for,for example, a molded article from a polyolefine-based resin. On theother hand, in the case that the use ratio of the acrylic polyol resin(VI-A) exceeds 90% by weight, crosslinking becomes insufficient, andthere lower solvent resistance and weatherability. A preferred use ratioof the acrylic polyol resin (VI-A) is 60-80% by weight and, accordingly,a preferred use ratio of the polyisocyanate compounds (VI-B) is 20-40%by weight. In the case that the use ratio of the polyisocyanatecompounds (VI-B) is less than 20% by weight, curability becomesinsufficient and, an intermolecular crosslinking density lowers and, asa result, there is readily caused a situation that there are notsufficiently shown characteristics by using the crosslinked particles.On the other hand, in the case of exceeding 40% by weight, a curedcoating layer becomes too rigid and, emulsifying through phase inversionoften becomes difficult or quite impossible. Accordingly, it is notpreferred in both cases.

The present invention basically intends to provide a method for thepreparation of crosslinked particles comprising dispersing andcrosslinking a mixture of the acrylic polyol resin (VI-A) havingcarboxylic groups and crosslinkable functional groups with thepolyisocyanate compounds (VI-B) (a hydrophobic crosslinking agent) intoa water-based medium, or a method for the preparation ofurethane-urea/ethylenic resin composite type crosslinked particlesobtained by polymerizing a polymerizable ethylenic unsaturated compoundcontaining at least the hydroxyakyl (meth)acrylate composition modifiedby a small amount of lactones in water in which crosslinkedurethane-urea particles are dispersed, and, in addition, intends toprovide a coating which comprises containing thus-obtained variouscrosslinked particles as essential thin layer-formable resin components.

Herein, specified crosslinked particles to be employed in the presentinvention are obtained by dispersing and crosslinking a mixture of theacrylic polyol resin (VI-A) having carboxylic groups and crosslinkablefunctional groups with the polyisocyanate compounds (VI-B) (ahydrophobic crosslinking agent) into a water-based medium.

That is, the acrylic polyol resin (VI-A) to be employed for thepreparation of the specified crosslinked particles is a so-called selfwater-dispersible resin which simultaneously contains carboxylic groupswhich are a hydrophilic segment and crosslinkable functional groupswhich can react with the polyisocyanate compounds (VI-B) (a hydrophobiccrosslinking agent), and which means a resin which forms an O/Wdiscontinuous phase by emulsifying through a phase inversion whileadding water into an organic continuous phase (O).

In the case, it is a resin which is basically different from awater-soluble resin. Further, such the self water-dispersible resin isaccompanied by a physical and chemical phenomenon of a phase inversionfrom organic phase to water phase, and it has an ability of forming O/Wparticles in a water-based medium. In the case, hydrophobic substancescan be taken into particles.

The present invention intends to provide highly-crosslinked particleswhich have not been conventionally prepared by emulsifying thepolyisocyanate compounds (VI-B) (a hydrophobic crosslinking agent)together with the self water-dispersible resin into a water-based mediumthrough a phase inversion utilizing characteristics of such the selfwater-dispersible resin to take the polyisocyanate compounds (VI-B) intothe particles, and then, by proceeding a crosslinking reaction.

Further, a coating which contains such the crosslinked particles as anessential component can provide a coating layer having a very excellentcorrosion resistance.

If the acrylic polyol resin (VI-A) is a water-soluble resin, sinceparticles are formed by the hydrophobic crosslinking agent whichfunctions as a nucleus, stability becomes insufficient in thewater-based medium, and it is apt to be readily gelled during proceedingthe crosslinking reaction, or it tends to gel with a lapse of time.

The crosslinked particles obtained by a method for the preparation inthe present invention are mixed with the acrylic polyol resin (VI-A) andthe polyisocyanate compounds (VI-B) (a hydrophobic crosslinking agent),followed by dispersing into a water-based medium by adding a basicmaterial.

As the basic material to be employed herein, volatile tertiary aminesare preferably employed and, contrarily, inorganic basic compoundsunpreferably remain in a coating layer, and show a tendency that waterresistance becomes worse.

As the amines, there are exemplified particularly typical examplesalone, and there are enumerated a variety of alkyl amines such astrimethylamine or triethylamine; a variety of alcohol amines such asdimethylaminoethanol, diethanolamine or aminomethylpropanol; and avariety of cyclic amines such as morpholine.

Subsequently, after dispersing into a water-based medium, solvents areoptionally removed and, in the case that the polyisocyanate compoundsare contained, heating is conducted at 50-60° C., for 1 hour or so, and,in the case that an epoxy resin is contained, heating is conducted at80° C. or so for 1-2 hours or so to accelerate a crosslinking, and then,there can be obtained a water dispersion liquid containing crosslinkedparticles having a desired solid-content by removing water.

Further, in the present invention, there can be employed the followingtype ones as a urethane/acrylic resin composite type crosslinkedparticles. That is, the type ones are obtained by 1) first of all, awater dispersion containing crosslinked urethane particles areindependently prepared, subsequently, 2) a low polymerizable vinyl-basedmonomer in relation to the present invention is added dropwise into thewater dispersion under the presence of a radical polymerizationinitiator (it is a so-called seed polymerization method) to effectpolymerization.

Herein, as a method for obtaining a water dispersion of crosslinkedurethane particles, three methods are outlined. Since all methods are apublicly-known method to a skilled person in the art, outlines alone areillustrated. First of those is a method in which there is emulsified apolyisocyanate prepolymer having isocyanate groups at terminals in themolecule under the presence of an emulsifier and/or a water-solubleresin for a protecting colloid, and then, the isocyanate groups atterminals are crosslinked by adding a crosslinking agent such aspolyamines to obtain desired crosslinked particles.

Second of those is a method in which any one of anionic, cationic, andnonionic hydrophilic groups is introduced as pendant groups into amolecule of the polyisocyanate-prepolymer having an isocyanate groups atterminals, whereby, the prepolymer itself is self-emulsified withoutusing an auxiliary agent such as an emulsifier and, polyamines which area crosslinking agent are likewise added to prepare crosslinkedparticles.

Third of those is a method in which the same prepolymer as in the secondmethod is mixed with the hydrophobic polyisocyanate compounds, and then,emulsified by a phase inversion into a water-based medium, and apolyamine which is a crosslinking agent is added after introducing thehydrophobic polyisocyanate compounds into particles to preparecrosslinked particles.

Of those, in the second and third methods, although auxiliary agents maybe even simultaneously employed, it is preferred to not simultaneouslyemploy the auxiliary agents in consideration of succeeding steps.

For that reason, in the present invention, it is required that it isoften desired to employ crosslinked urethane particles obtained by thesecond and third methods in which the auxiliary agents such asemulsifiers are not simultaneously employed.

In a polymerization step of a polymerizable vinyl-based monomer typifiedby the hydroxyakyl(meth)acrylate composition modified by a small amountof lactones in relation to the present invention by employing thecrosslinked urethane particles dispersion as a seed, a characteristicpart is to employ a crosslinked urethane water dispersion as a seedmaterial and, needless to say, as a method for the polymerization of thevinyl-based monomer, conventional methods can be employed without anymodification.

As the radical polymerization initiators, any one of water-soluble oroil-soluble ones can be employed and, above all, water-soluble radicalinitiators can be more readily employed, and those can also contributeto a dispersion stability in the water dispersion of a composite resinobtained, accordingly, those are more desired.

As weight ratio of solid components in the crosslinked urethane resin(GU) with respect to the polymerizable vinyl-based monomer (VM),although there can be applied a range of 0/100<GU/VM<100/0, in the casethat there are not employed auxiliary agents such as emulsifiers at all,it appropriately ranges in 20/80<GU/VM<100/0 depending upon a geldensity (a crosslinking density) and dispersion stability of agel-urethane to be employed.

However, since a main purpose of modification for a composite is toallow to manifest all properties of both the above-described crosslinkedurethane resin (GU) and a polymer derived from the polymerizablevinyl-based monomer (VM), in order to allow to manifest all theproperties of both resins, it ranges in 10/90<GU/VM<90/10, andpreferably in 25/75<GU/VM<75/25, and the range is particularlyrecommended.

The polymerizable vinyl-based monomers may be even added dropwise to aseed system maintained under conditions of reaction temperatures or, maybe even added dropwise to a seed system maintained under conditions ofreaction temperatures after having absorbed the polymerizablevinyl-based monomers in swelled seed particles under conditions ofreaction temperatures.

Such the dropwise addition is mainly conducted for the purpose ofcontrolling a reaction heat accompanied by polymerization, accordingly,a method for the dropwise addition is not particularly limited.

In thus-obtained composite type water dispersion of a crosslinkedurethane resin/vinyl-based resin, in the case of employing amultifunctional vinyl-based monomer, networks derived from both resinsare intertwined each other and the so-called IPN is formed and, as aresult, there can be obtained a product having more excellent solventresistance and chemical resistance, and a high tensile force.

Incidentally, in a method of the present invention, there can be formeda coating layer which is particularly excellent in corrosion resistancefrom a coating containing crosslinked particles having characteristicsas described hereinabove as an essential thin layer-formable resincomponent, accordingly, the present inventor names the method as a gelparticle layer-forming method.

That is, the present invention intends to provide a method for theformation of a coating layer having a corrosion resistance for a metal,namely, the gel particle layer-forming method in which there is employeda coating agent containing more than 50% by weight of theabove-described crosslinked particles having a particle diameter of notmore than 1 micron (μm) as an essential thin layer-formable resincomponent in the case of the formation of a coating thin layer havingcorrosion resistance for a metal or a decorative coating layer havingcorrosion resistance for a metal by coating a liquid coating agent (aliquid coating) onto a metal to be coated and drying and, by heating ata temperature of 100-350° C. or so for a fixed time of period.

After all, there was found that in the gel particle layer-formingmethod, crosslinked particles themselves are crosslinked each otheraccording to a design level of the crosslinked particles, whereby, acontinuous thin layer can be formed, or a continuous thin layer can beformed through a crosslinking between a particle and a particle byemploying together a crosslinking agent and, further, the method doesnot cause any inconveniences and, as a result, any problems even thoughthere is employed together a melamine resin-based curing agent having aproblem in a conventional method for forming a layer as a crosslinkingagent, and the present invention has been completed.

In other words, a following mechanism is guessed, that is, thecrosslinked particles are formed by strong bonds against a variety ofchemicals such as acids and alkalis and, in addition, a main componentfor a thin layer-formable resin is constructed by the crosslinkedparticles crosslinked in a level of not being apt to swell in solvents,whereby, even though crosslinked bonds between particles are a so-calledweak bond against chemicals such as methylene ether bond which isproduced in the case of employing the melamine resin-based curing agent,since the bond is protected from every direction by the crosslinkedparticles, those becomes not apt to be directly attacked by chemicals,as a result therefrom, there manifests an excellent effect that it issuppressed to cause a problem such as decomposition.

In addition, the crosslinked particles are a peculiar one moleculecompound having a gelled (cross-linked) giant molecular weight. Ifroughly estimated, a molecular weight in a one molecule compoundparticle having a size of 1 μm will attain to at least 300,000,000.

Needless to say, a thin layer-formable resin to be employed in a form ofa conventional coating is of a level of a so-called prepolymer, and themolecular weight is 100000 or so to the utmost.

In the gel layer-formable method in the present invention which startsfrom the crosslinked particles having a giant molecular weight, acontinuous crosslinked gel layer is formed by production amount ofchemical binds which are exceedingly slight compared to productionamount of chemical binds to be required for preparing a crosslinked gelfilm having a sufficiently high molecular weight by forming a coatinglayer through crosslinking thereof, that is, by production amount of 1piece per 0.3 billion pieces, whereby, a molecular weight in a coatinglayer produced can attain to an extraordinary level.

In other words, in such the gel particles layer-formable method whichstarts from a giant molecule, the production amount of chemical binds tobe required in layer-forming may be even substantially very slightcompared to conventional methods.

This means that temperature, time of period, or an amount of a catalystwhich is a condition to be required for producing a chemical bond can beall reduced or shortened and, particularly, in the case that across-linking agent is simultaneously employed, use amount thereof canbe more reduced.

This is also a large characteristics in the present invention.

In construction of the above-described liquid coating agent (a liquidcoating) in the present invention, more than 50% by weight of thecross-linked particles are desirably contained as a resin component forfilm-forming (a thin layer-formable resin component).

Even in the case of being less than 50% by weight, although an onlyabout effect is shown, it is not sufficient. Preferably, it is not lessthan 70% by weight.

In order to obtain a glossy coating surface having smoothness, it maysafely be said that there is required a particle diameter of not morethan 1 m by all means and, moreover, a smaller diameter is morepreferred. Further, it is desired to contain a component having aspecified chemical bond such as urethane bond, whereby, a coating layerobtained becomes hard, flexible, and tough.

By giving a so-called active atomic group (a polar group) such ashydroxyl group, carboxylic group, glycidyl group, or urethane bond intothe particles, gel particles themselves are self crosslinked, or bycrosslinking between particles in the form of employing together with acuring agent (a cross-linking agent), a continuous thin layer can beformed herein.

Such the crosslinking reaction is usually induced by forcibly heating,and completed.

Although depending upon a kind of a reactive active group (a reactivepolar group), in order to complete the reaction within an appropriatetime of period, there is by all means required a temperature of not lessthan 100° C., and preferably not less than 120° C.

If the reactive active group (are active polar group) is a variety ofunsaturated bonds such as vinyl group, since crosslinking is caused evenby irradiation of so-called radiation rays such as an ultraviolet rayand an electron beam, although it does not always require to be heated,heating is also preferably conducted in order to proceed a reaction byaccelerating a close fusion of particles themselves.

In the case that the curing agent is simultaneously employed, as suchthe curing agent, there can be employed a variety of compounds such as amelamine resin, a phenol resin, and an isocyanate compound and, in orderto obtain a coating layer having a light color by exposure and heating,the melamine resin is preferably employed.

For example, in a water-based coating, a water-soluble orwater-dispersible melamine resin is exemplified, and particularlytypical examples alone are exemplified below, which include ahexamethoxymethyl melamine such as “MW12LF” manufactured by SanwaChemical, Ltd., “Nikalak MW-30” manufactured by Nihon Carbide KagakuKogyo, Ltd., or “Sumimal M-100C” manufactured by Sumitomo Kagaku Kogyo,Ltd., and a variety of methoxymethyl melamines which have free methylolgroup such as “Sumimal M-40W” and “Sumimal M-30W” manufactured bySumitomo Kagaku Kogyo, Ltd.

Further, there can be also employed a melamine resin in which aso-called hydrophobic melamine resin diluted in a dilution ratio of notmore than 20% by weight using water/methanol mixed solvent (weightratio=35/65) is dispersed by a water-soluble resin or a dispersant and,above all, the hexamethoxy melamine resin is employed.

And, use amount of the curing agent appropriately ranges in 1-25% byweight, and preferably 3-15% by weight based on amount of thecrosslinked particles. As a thin layer-formable resin component otherthan the curing agent typified by the crosslinked particles and theabove-described melamine resin, there can be also simultaneouslyemployed a thermoplastic resin having a reactive active group (areactive polar group), and use amount of the thermoplastic resin havinga reactive active group appropriately ranges in not more than 30% byweight, and preferably not more than 20% by weight in the thinlayer-formable resin component.

When there more increases the use amount of components other than thecuring agent, various inherent properties in the gel layer-formingmethod are more deteriorated and, there becomes also more deterioratedan effect for manifesting a high corrosion resistance which is a targetproperty.

Further, if an average molecular weight between crosslinking points inthe above-described various crosslinked particles ranges in 300-2,000,in the coating of the present invention essentially containing thecrosslinked particles, corrosion resistance becomes more preferred.

Incidentally, the average molecular weight between crosslinking pointsdescribed herein is shown by a weighted average value after havingcalculated an average molecular weight per 1 piece of a functional grouptaking part in crosslinking in respective resins (also including thehydrophobic curing agent) to be formulated.

It is to be noted that a temperature for film-forming in the crosslinkedparticles is preferred in not more than 100° C.

In the case of crosslinked particles which do not form a thin layerwithout heating at a temperature of more than 100° C. even though avariety of solvents are employed as an auxiliary agent for film-forming,the temperature for film-forming should be designed so as to become notmore than 100° C. because of a difficulty in obtaining a coating layerwhich is excellent in corrosion resistance which is one of purposes inthe present invention and, also from a viewpoint of formulatingcomposition or a crosslinking density.

Further, in the case that the average molecular weight betweencrosslinking points is less than 300, that is, in the case that thecrosslinking density is exceedingly high, as a result, it affects to thetemperature for film-forming, fusion between particles or film-formation(thin layer-formation) become difficult, and various properties as acoating layer are unpreferably deteriorated.

On the other hand, in the case that the average molecular weight betweencrosslinking points becomes too large exceeding 3,000, that is, in thecase that the crosslinking density is low, as a result, the particlesbecome apt to swell in a solvent, resulting in that solvent resistancealso unpreferably lowers.

In the coating of the present invention, needless to say, pigments canbe also involved in the crosslinked particles which are an essentialcomponent in the coating. By involving the pigments in the crosslinkedparticles, the present invention has a merit of liberation from variousproblems by removing all drawbacks such as dispersibility andcolor-separation of pigments which have still become problematic untilnow.

Particularly, in a water-based coating, since a excellent dispersantdoes not exist and, pigments are mainly dispersed using a water-solubleresin and, there is applied a method that the pigments are added andinvolved. On the other hand, in the present invention, pigments can beoptionally involved without any modification in the crosslinkedparticles and, whereby, there can be removed an influence which dependsupon surface conditions of a variety of pigments. Moreover, since thepigments are covered by particles having a crosslinked structure,particles are not swelled or not dissolved by solvents contained in acomposition, whereby, there is also produced a merit that pigments arenot separated and an excellent dispersibility and stability are shown.

Specifically, the above-described acrylic polyol resin (VI-A) (a selfwater-dispersible resin) and the pigments are kneaded by apublicly-known and common method, for example, using a variety ofapparatuses such as a three-roll and a paint conditioner to prepare amill base, subsequently, the above-described polyisocyanate compound(VI-B) (a hydrophobic crosslinking agent) is mixed therewith and aminesare added, followed by dispersing into an aqueous medium.

After that, there is obtained a desired water dispersion in whichpigments are involved in crosslinked particles by acceleratingcrosslinking. Roughly, there is obtained a desired water dispersion inwhich pigments are involved through the means and steps as describedhereinabove.

Such the methods are particularly effective in the case of producingparticles by emulsifying through a phase inversion using the selfwater-dispersible resin. It is very difficult to prepare a such capsuleof pigments by a publicly-known and common means, for example, a methodsuch as an emulsion polymerization or a nonaqueous polymerization (anonaqueous-dispersion polymerization).

Herein, particularly typical examples alone are enumerated as pigmentsto be employed, and there are enumerated a variety of inorganic-basedpigments such as titanium dioxide (for example, Typek CR-95 (a titaniumoxide pigment manufactured by Ciba Geigy, A.G.)), an iron oxide, an ironoxide red, lead molybdenum, chromium oxide, and a chromate or carbonblack; or a variety of organic-based pigments such as aphthalocyanine-based pigment such as Phthalocyanine Blue andPhthalocyanine Green, Carbazole Violet, Anthrapyrimidine Yellow,Flavaslone Yellow, Isoindoline Yellow, Indaslone Blue or QuinaklidoneViolet, Quinaklidone-based Red, an azo pigment, and an anthraquinonepigment, etc.

Further, although the crosslinked particles as described hereinabove area water-based one, the crosslinked particles employed in the presentinvention can be employed in a wider composition range compared toso-called nonaqueous crosslinked particles obtained by a method such asthe nonaqueous polymerization (a nonaqueous-dispersion polymerization)and, moreover, a preparation process is also easy.

The crosslinked particles in the present invention can be readily movedinto a variety of polar organic solvents such as, for example, butanoland methylethylketone. In the case, it can be returned from carboxylicsalts to carboxylic acids by a reverse neutralization and, whereby, itcan be readily further moved.

As described hereinabove, in the present invention, water-basedcrosslinked particles can also become employed in a solvent system.However, although being a little, since it tends to become slightly poorin dispersion stability compared to a water-based one, it may safely besaid even that it rather matches with a water-based use in the methodfor the preparation of the crosslinked particles of the presentinvention and a coating obtained using the crosslinked particles.

The coating in relation to the present invention essentially containsthe above-described curable resin composition, and the coating isobtained by dissolving or dispersing the resin into water and, there canbe prepared a two-liquid coating composition or a single-liquid coatingcomposition by optionally formulating a variety of additives which areconventionally employed in a coating field, for example, an ultravioletray absorbent, a photostabilizer, an antioxidant, a coloring pigment, anextender pigment, a metallic pigment, an aluminum powder, a pearly micapowder, an anti-dropping agent or an anti-sedimentation agent, aleveling agent, a dispersant, a defoaming agent, an antistatic agent, acatalyst for curing, a flowability-adjusting agent, a celluloseacetate-butylate, and a thinner which are publicly- and commonly-known.Further, there can be employed other resins such as an epoxy resin and apolyester resin or a high molecular weight compound which has a goodcompatibility within a range in which an effect by the present inventionis not decreased.

Thus-obtained coating can be coated by publicly- and commonly-knownmethods such as spray coating, roller coating, and brush coating. It isto be noted that it goes without saying that the resin composition for acoating of the present invention can be employed as a clear coating inwhich pigments are not employed, or an enamel coating in which pigmentsare employed.

In the coating in relation to the present invention, there can beactualized a more exceedingly excellent acid resistance which does notinclude any problems compared to a coating prepared from a conventionalpolyol and melamine resin even though being further simultaneouslyemployed other polyols and crosslinking agents (for example, a melamineresin). In the coating in relation to the present invention, in the caseof simultaneously employing other polyol resins and melamine resins, thecontent of the curable resin composition of the present invention is notless than 10% by weight, and preferably not less than 25% by weight, themelamine resins are not more than 30% by weight, and preferably not lessmore than 20% by weight, in total solid resin components.

In the case that the curable resin composition of the present inventionis less than 10% by weight or, the melamine resins are more than 30% byweight, an acid resistance cannot be unpreferably elevated.

In the curable resin composition of the present invention, above all, inorder to elevate weatherability such as retention of a gloss duringexposure and a high extentionable property, there is preferably employeda mixture composed of an ultraviolet ray absorbent/hindered amine-basedphoto-stabilizer=(40-60)/(60-40) (solid content ratio) within a range of0-10 wt % based on solid components in the curable oligomer (a(co)polymer) (a). In the case that addition amount is not less than 10wt %, since a price of a coating becomes expensive and, crystallines areoccasionally formed at a low temperature and water resistanceoccasionally lowers, and a resin solution occasionally discolors, it isnot preferred so much. Even in an outside value of the above mixingratio of the ultraviolet ray absorbent with respect to the hinderedamine-based photo-stabilizer, although an effectiveness is observed, theeffectiveness is excellently observed in a range of the above mixingratio.

As typical examples of the ultraviolet ray absorbent which ispublicly-known, there can be preferably employed a benzotriazole-basedultraviolet ray absorbent such as Tinuvin 900, Tinuvin 383, and TinuvinP (all of those are manufactured by Ciba Geigy), an anilideoxalate-based ultraviolet ray absorbent such as Sandbar 3206(manufactured by Sand), etc. A fixed amount of the absorbents may beadded in a terminating period of a copolymerization reaction of theacrylic polyol or in the preparation of a coating. On the other hand, inthe case of T-17, T-37, and T-38 (all of those are a product by AdekaArgus Kagaku, Ltd.) which are a reactive ultraviolet ray absorbentcontaining an organic group having an ultraviolet ray absorbing abilitysuch as an O-hydroxybenzophenone group and an ethylenic copolymerizableunsaturated bond such as methacrylic acid group in an identicalmolecule, a fixed amount thereof may be simultaneously introduced at acopolymerization step of the acrylic polyol resin (VI-A) components.

As examples of the hindered amine-based photo-stabilizer, there can bepreferably employed a piperidine-based one which is usually called HALS(HALS), and which typically includes4-benzoyloxy-2,2,6,6-tetramethylpiperidine,bis(2,2,6,6-tetramethyl-4-piperidine)sebacate, or Tinuvin 144, 292, and765 (all of those are a product manufactured by Ciba Geigy, A.G.), MARKLA-57, 62, 63, 67, and 68 (all of those are a product by Adeka ArgusKagaku, Ltd.), Sanol LS292 (manufactured by Sankyo), and Sandbar 3058(manufactured by Sand). A fixed amount of the stabilizers may be addedin a terminating period of a copolymerization reaction of the curableoligomer (a (co)polymer) (a) or in the preparation of a coating. In thecase of a hindered amine-based compound containing an organic grouphaving a photo-stabilizing ability and an ethylenic copolymerizableunsaturated bond such as (meth)acrylic acid group such as the MARKLA-82, 87, and T-41 (all of those are a product by Adeka Argus Kagaku,Ltd.), a fixed amount thereof may be simultaneously introduced at asynthesis step of the curable oligomer (a (co)polymer) (a).

Further, in order to increase an effectiveness thereof, optionally,there can be simultaneously employed an antioxidant such as “SumilizerBHT” (a product manufactured by Sumitomo Kagaku Kogyo, Ltd.), “SeenoxBCS” (a product manufactured by Shiroishi Calcium, Ltd.), “Irganox 1010or 1076” (a product manufactured by Ciba Geigy, A.G.), “Noclizer TNP” (aproduct manufactured by Ohuchi Shinko, Ltd.), and “Antioxidant KB” (aproduct manufactured by West Germany/Bayer. A.G.), which are well knownand commonly-used.

As the catalysts for curing, there are enumerated a phosphate, anorganic acid such as dodecylbenzene sulphonic acid or paratoluenesulphonic acid and an amine salt thereof, an organic tin compound suchas dibutyltin dilaurate and dibutyltin dimaleate and a chelatingcompound thereof, etc.

As the extender pigment, for example, there are enumerated kaoline,talc, silica, mica, barium sulphate, and calcium carbonate, etc.

As the anti-dropping agent or an anti-sedimentation agent, for example,there can be preferably employed bentonite, a castor oil wax, an amidewax, a micro gel (for example, MG100S (manufactured by Dainippon Ink)),and aluminum acetate, etc.

As the levelling agent, for example, there can be preferably employed asilicone-based surface active agent such as KF69, Kp321 and Kp301(manufactured by Shin-etsu Kagaku), a silicone-based surface activeagent such as Modaflow (a surface-adjusting agent manufactured byMitsubishi Monsant) and BYK301 and 358 (manufactured by BickchemieJapan), and Diaaid AD9001 (manufactured by Mitsubishi Rayon), etc.

As the dispersant, for example, there can be preferably employedAnti-Terra U or Anti-Terra P, and Disperbyk-101 (manufactured byBickchemie Japan), etc. As the defoaming agent, for example, there canbe preferably employed BYK-0 (manufactured by Bickchemie Japan), etc.

As the thinner, there can be preferably employed conventionallypublicly-known aromatic compounds, alcohols, ketones, ester compounds,or a mixture thereof, etc.

As the antistatic agent, for example, there can be preferably employedEsocard C25 (manufactured by Lion Armer), etc.

In the case of preparing the coating composition of the presentinvention, there are mixed the above-described acrylic polyol resin(VI-A), the polyisocyanate compound (VI-B), and optionally, additivessuch as curing agents and pigments, and uniformly dispersed by adispersing machine such as a sand grind mill, a ball mill, and Atlighterto prepare a curable type coating composition.

A method for coating the curable coating composition (a coatingcomposition) of the present invention is as follows.

That is, an article to be coated is cleaned by a publicly-known dewaxingcleaning, for example, dewaxing by an organic solvent such as1,1,1-trichloroethane, cleaning by an alkali, cleaning by an acid,wiping by a solvent, etc., further, optionally, in order to furtherelevate an adhesive power of a coating to the article to be coated, forexample, the coating composition of the present invention is directlycoated by an air-spraying coating method and an airless coating methodafter coating a primer such as Primac NO. 1500 (manufactured by NihonYushi), and optionally, it is set for 0.5-120 minutes, and preferably1-20 minutes, and thermally cured (baked) at a low temperature of90-140° C., and preferably 100-120° C. A clear coating may be evencoated onto a base coat coating which is an under layer by a wet-on-wetmethod. In the present invention, since curing can be conducted at a lowtemperature of not more than 140° C. by the above-describedconstruction, it does not give a damage even on a polyolefine-basedresin molded article, and there can be formed a coating layer havingexcellent properties of a coating layer.

In the case that a primer is coated, layer thickness after drying isgenerally 3-20 μm, and preferably 5-15 μm. Further, layer thickness ofthe clear coat coating is generally 15-45 μm, and preferably 20-35 μm.As a method using the coating composition of the present invention,there are enumerated a 2-coat/1-baking type coating method and3-coat/2-baking type coating method, etc.

Herein, the 2-coat/1-baking type method is one of coating methods by anover coating and, first of all, there is coated a base coat coating inwhich pigments and/or metal powder are formulated in a large amount, andthen, there is coated a transparent clear coating or a top coating whichis a color clear coating containing a small amount of pigments, andthose coatings are simultaneously baked. In the case of the2-coat/1-baking type coating method, a usual coating composition isemployed as a base coat and, the coating composition of the presentinvention can be employed as a top coat. In the case of the3-coat/2-baking type coating method, there is coated and baked a coatingin which there are formulated pigments, dyes, and/or metal powder and,there is further coated thereon and baked a base coat in which there areformulated pigments, dyes, and/or metal powder, and then, there iscoated thereon and collectively baked a transparent clear coating or atop coat which is a color clear coating containing a small amount ofpigments or dyes.

VII

Hereinafter, the present invention VII is illustrated in detail.

(A) Acrylic Resin

Acrylic polyol resin (VII-A) (also called the component (VII-A)) is anacrylic resin having hydroxyl group composed of thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones illustrated in the present invention I.

By polymerizing the hydroxyalkyl(meth)acrylate composition (a) modifiedby a small amount of lactones employed in the present invention, a mainchain is substantially composed of an acrylic copolymer chain, whereby,there are improved weatherability, solvent resistance, and waterresistance in a cured article.

In the acrylic polyol resin (VII-A), a molecular weight and a hydroxylvalue, etc. are not particularly limited, and a number molecular weightis preferably 1,000-50,000, and more preferably 2,000-30,000 from aviewpoint of physical properties in a coating layer such as strength anddurability. Further, the hydroxyl value is 10-300 mg-KOH/g, and morepreferably 30-150 mg-KOH/g from a viewpoint of physical properties in acoating layer such as strength and durability. Such the component (a)may be employed solely or in combination of two or more kinds.

The acrylic polyol resin (VII-A), in addition to thehydroxyalkyl(meth)acrylate composition (a) modified by a small amount oflactones, can be obtained, for example, by copolymerization of othervinyl monomers having hydroxyl group with monomers for introducing afunctional group which is illustrated hereinafter, and a (meth)acrylicacid derivative, etc.

Other Vinyl Monomers having Hydroxyl Group

As specific examples of the other vinyl monomers having hydroxyl groupcontained as a copolymerizing component in the acrylic polyol resin(VII-A), there are enumerated the monomers exemplified in the presentinvention I.

For introducing acid anhydride groups into the acrylic polyol resin(VII-A), for example, maleic anhydride and itaconic anhydride, etc. arecopolymerized and, for introducing epoxy groups, for example,glycidyl(meth)acrylate, etc. are copolymerized, and for introducingcarboxylic groups, for example, there are copolymerized unsaturatedcarboxylic acids such as (meth)acrylic acid, maleic acid, fumaric acid,and itaconic acid, etc. and, for introducing amino groups, for example,there are copolymerized vinyl-based monomers containing an amino groupselected from the group consisting of primary amino group, secondaryamino group, and tertiary amino group.

As a typical example of the vinyl-based monomers containing an aminogroup, there are enumerated the vinyl-based monomers exemplified in thepresent invention I.

Derivatives of acrylic acid or methacrylic acid copolymerizable with theother vinyl monomers having hydroxyl group are not particularly limitedand, as specific examples, there are enumerated methyl(meth)acrylate,ethyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate,stearyl(meth)acrylate, benzyl(meth)acrylate, cyclohexyl (meth)acrylate,trifluoroethyl(meth)acrylate, pentafluoropropyl (meth)acrylate,perfluorocyclohexyl(meth)acrylate, (meth)acrylonitrile, (meth)acrylicamide, α-ethyl(meth)acrylic amide, N-butoxymethyl(meth)acrylic amide,N,N-dimethyl acrylic amide, N-methyl acrylic amide, andN-methylol(meth)acrylic amide, a macromer manufactured by Toa GoseiKagaku Kogyo which includes AS-6, AN-6, AA-6, AB-6, and AK-6, etc, vinylcompounds containing a phosphoric acid ester group which is acondensation product of hydroxyalkyl(meth)acrylates with phosphoric acidor a phosphate, and (meth)acrylates containing a urethane bond and asiloxane bond.

The acrylic polyol resin (A) may even contain a portion of a urethanebond and a siloxane bond in a main chain within a range not exceeding50% (% by weight, hereinafter, the same) and, further, may even containa unit derived from monomers other than (meth)acrylic acid derivatives.The monomers are not particularly limited and, as a specific examplethereof, in addition to the monomers for introducing the functionalgroups, there are enumerated an aromatic hydrocarbon-based vinylcompound such as styrene, α-methylstyrene, chlorostyrene,styrenesulphonic acid, and vinyltoluene; unsaturated carboxylic acidsalts (an alkali metal salt, an ammonium salt, and an amine salt, etc.)of maleic acid, fumaric acid, and itaconic acid, etc.; unsaturatedcarboxylic acid esters such as a diester or a half ester of theunsaturated carboxylic acid with a linear or branched alcohol having acarbon number of 1-20; a vinylester such as vinyl acetate, vinylpropionate, and diallyl phthalate, and an allyl compound; vinylcompounds having amide group such as itaconic diamide, croton amide,maleic diamide, fumaric diamide, and N-vinylpyrrolidone; other vinylcompounds such as methylvinyl ether, cyclohexylvinyl ether, vinylchloride, vinylidene chloride, chloroprene, propylene, butadiene,isoprene, fluoroolefine, maleimide, and vinyl sulphonic acid, etc.

As a polymerization method for the acrylic polyol resin (A), a usualpolymerization method is employed and, a solution polymerization isparticularly preferred from a viewpoint of easiness of synthesis, inwhich there is employed an azo-based radical initiator such asazobisisobutyronitrile. Molecular weight can be adjusted by using achain transfer agent such as n-dodecyl mercaptan and t-dodecyl mercaptanor by controlling a reaction temperature.

(B) Acrylic Copolymer Containing an Alkoxysilyl Group

One of the acrylic copolymer (VII-B) (called also the component (VII-B))containing an alkoxysilyl group is an acrylic copolymer containing atleast one, preferably, at least two alkoxysilyl groups having a groupshown by general formula (VII-2) described below in one molecule,

(in the formula, R¹ is an alkyl group having a carbon number of 1-10, R²and R³ are a hydrogen atom or a monovalent hydrocarbon group selectedfrom an alkyl group, aryl group, and aralkyl group which have a carbonnumber of 1-10, a is the number of a substituent group, and it is aninteger of 0, 1, or 2).

Another one of the acrylic copolymer (VII-B) containing an alkoxysilylgroup to be employed in the present invention is an acrylic copolymercontaining an alkoxysilyl group, which has at least one, preferably, atleast two groups shown by the above-described general formula (VII-2) atterminals or side chains in one molecule, and which has at least onegroup selected from an acid anhydride group, an epoxy group, an aminogroup, and carboxylic group.

In the general formula (VII-2), R¹ is more preferably an alkyl group ofa carbon number of 1-4. In the case that the carbon number exceeds 10,or the R¹ is, for example, phenyl group or benzyl group other than thealkyl group, there lowers a reactivity in the alkoxysilyl group. As aspecific example of the R¹, there are enumerated methyl, ethyl,n-propyl, iso-propyl, n-butyl, and iso-butyl group, etc. As the alkylgroup having a carbon number of 1-10 which is one kind of the R², thereare enumerated the same groups as in the R¹ and, as the aryl group, forexample, there are enumerated phenyl group, tolyl group, xylyl group,etc., as the aralkyl group, for example, there is enumerated benzylgroup, etc.

Since in the copolymer (VII-B), a main chain substantially consists ofan acrylic copolymer chain, weatherability, solvent resistance, andwater resistance are improved in a cured article.

Further, since the alkoxysilyl group connects to carbon, waterresistance, alkali resistance, and acid resistance, etc. are moreimproved.

The alkoxysilyl group reacts with hydroxyl group derived from thehydroxyalkyl(meth)acrylate monomer (a) modified by a small amount oflactones, and it contributes to crosslinking, and the alkoxysilyl groupitself also reacts with each other, and it is a component forcontributing to crosslinking. In the case that the number of thealkoxysilyl group in one molecule is less than 1 piece in the copolymer(VII-B), there lowers solvent resistance in physical properties of acoating layer.

The group selected from an acid anhydride group, an epoxy group, anamino group, and carboxylic group in the copolymer (VII-B) reacts withthe group selected from an acid anhydride group, an epoxy group, anamino group, and carboxylic group in the acrylic polyol resin (VII-A) ina combination of the acid anhydride group/epoxy group, amino group/epoxygroup, or carboxylic group/epoxy group, and it elevates solventresistance and water resistance in a cured coating layer from thecomposition of the present invention.

The number of the group selected from an acid anhydride group, an epoxygroup, an amino group, and carboxylic group is not less than 1 piece per1 molecule of the copolymer (VII-B) and, preferably 2-30 pieces from aviewpoint of solvent resistance and water resistance in the curedcoating layer.

From a viewpoint of physical properties (strength, durability) of acoating layer, a number average molecular weight in the copolymer(VII-B) is 1,000-30,000, and more preferably 3,000-25,000.

The copolymer (VII-B) can be obtained, for example, by copolymerizationof a monomer (VII-b) containing the alkoxysilyl group with at least oneof (meth)acrylic acid, and a derivative therefrom, or bycopolymerization of a monomer (VII-b) containing the alkoxysilyl groupwith a monomer for introducing a functional group which is describedlater, (meth)acrylic acid, and a derivative therefrom.

The monomer containing the alkoxysilyl group is not particularly limitedexcept that it has a polymerizable unsaturated double bond and thealkoxysilyl group represented by the above-described general formula(VII-2) and, as a specific example thereof, for example, there areenumerated the following compounds.

There are enumerated (meth)acrylates having the alkoxysilyl groupthrough urethane bond or a siloxane bond at terminal. These may be evensolely or in combination of two or more kinds.

Proportion of the monomer containing the alkoxysilyl group is preferably5-90% by weight, and more preferably 11-70% by weight in the copolymer(VII-B) from a viewpoint of curability of a composition and durabilityof a coating layer.

For introducing the acid anhydride group into the copolymer (VII-B), forexample, there may be copolymerized the monomers exemplified forintroducing the acid anhydride group, epoxy group, carboxylic group, andamino group into the acrylic polyol resin (VII-A).

The (meth)acrylic acid or derivatives thereof to be employed forintroducing carboxylic group are not particularly limited and, asspecific examples, there are enumerated methyl(meth)acrylate,ethyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate,stearyl(meth)acrylate, benzyl(meth)acrylate, cyclohexyl (meth)acrylate,trifluoroethyl(meth)acrylate, pentafluoropropyl (meth)acrylate,perfluorocyclohexyl(meth)acrylate, (meth)acrylonitrile, (meth)acrylicamide, α-ethyl(meth)acrylic amide, N-butoxymethyl(meth)acrylic amide,N,N-dimethyl acrylic amide, N-methyl acrylic amide,2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,N-methylol(meth)acrylic amide, Alonix M-5700 manufactured by Toa GoseiKagaku Kogyo, a macromer manufactured by Toa Gosei Kagaku Kogyo whichincludes AS-6, AN-6, AA-6, AB-6, and AK-5, etc, Placcel FA-1, PlaccelFA-A, Placcel FM-1, and Placcel FM-4, etc. manufactured by DaicelChemical Industries, Ltd., vinyl compounds containing a phosphoric acidester group which is a condensed product of hydroxyalkyl(meth)acrylateswith phosphoric acid or a phosphate, and (meth)acrylates containing aurethane bond and a siloxane bond, etc.

Further, the copolymer (B) may even contain units of a urethane bond anda siloxane bond in a main chain within a range not exceeding 50% and,further, may even contain units of monomers other than (meth)acrylicacid derivatives.

The monomers are not particularly limited and, as a specific examplethereof, in addition to the above-described monomers for introducingfunctional groups, there are enumerated an aromatic hydrocarbon-basedvinyl compound such as styrene, α-methylstyrene, chlorostyrene,styrenesulphonic acid, 4-hydroxystyrene, and vinyltoluene; unsaturatedcarboxylic acid salts (an alkali metal salt, an ammonium salt, and anamine salt, etc.) such as maleic acid, fumaric acid, and itaconic acid,unsaturated carboxylic acid esters such as a diester or a half ester ofthe unsaturated carboxylic acid with a linear or branched alcohol havinga carbon number of 1-20; a vinylester such as vinyl acetate, vinylpropionate, and diallyl phthalate, and an allyl compound; vinylcompounds having amide group such as itaconic diamide, croton amide,maleic diamide, fumaric diamide, and N-vinylpyrrolidone; other vinylcompounds such as 2-hydroxyethylvinyl ether, methylvinyl ether,cyclohexylvinyl ether, vinyl chloride, vinylidene chloride, chloroprene,propylene, butadiene, isoprene, a fluoroolefine, maleimide, and vinylsulphonic acid, etc.

The copolymer (VII-B) can be obtained, for example, by a method shown inJP-A-54036395 Official Gazette, etc., and a solution polymerizationmethod is most preferred from a viewpoint of easiness of synthesis, inwhich there is employed an azo-based radical initiator such asazobisisobutyronitrile.

In the solution polymerization method, a molecular weight can beadjusted by using a chain transfer agent such as n-dodecyl mercaptan,t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyl triethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyl methyldiethoxysilane,(CH₃O)₃—Si—S—S—Si—(OCH₃)₃, and (CH₃O)₃—Si—S₈—Si—(OCH₃)₃. Particularly,the alkoxysilyl group can be introduced in terminals of a polymer byusing the chain transfer agent having the alkoxysilyl group in themolecule, for example, γ-mercaptopropyl trimethoxysilane.

As solvents to be employed in the solution polymerization, there may beemployed the solvents to be employed in the preparation of the acrylicpolyol resin in the present invention I.

As use proportion of the component (VII-A) with respect to the component(VII-B), the component (VII-A)/the component (VII-B) is preferably(2-50)/(30-80) by weight ratio. In the case that the component(VII-A)/the component (VII-B) exceeds the above range, physicalproperties such as water resistance lowers in a coating layer and, inthe case of less than the above range, there does not becomesufficiently obtained an effect for improving an outer appearance andhardness of a coating layer by adding the component (VII-A).

In the component (VII-A) and the component (VII-B), reactive functionalgroups are separately contained in combination of the acid anhydridegroup/epoxy group; the amino group/epoxy group; and carboxylicgroup/epoxy group, and the combination may contain one, or two or morecombination.

(C) Catalyst for Curing (VII-C)

As the catalyst for curing (VII-C) to be employed in the presentinvention, for example, there are enumerated an organic tin compoundsuch as dibutyltin dilaurate, dibutyltin dilmaleate, dioctyltindilaurate, dioctyltin dimaleate, and tin octylate; phosphoric acid or aphosphate such as monomethyl phosphate, monoethyl phosphate, monobutylphosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate,diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecylphosphate; propyleneoxide, butyleneoxide, cyclohexeneoxide,glycidylmethacrylate, glycidol, acrylic glycidylether, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyl triethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, a compound shown by a formula described below,

Kardula E manufactured by Yuka Shell Epoxy, Ltd., an adduct of an epoxycompound with a phosphoric acid and/or an acidic monophosphate such asEpikote 828 and Epikote 1001 manufactured by Yuka Shell Epoxy, Ltd.;organic titanate compounds; organic aluminum compounds; acidic compoundssuch as maleic acid and paratoluene sulphonic acid; amines such as hexylamine, di-2-ethylhexyl amine, N,N-dimethyldodecyl amine, and dodecylamine; a mixture or reaction product of the amines with the acidicphosphates; and alkali compounds such as sodium hydroxide and potassiumhydroxide, etc.

Of the catalysts for curing (VII-C), there are preferred the organic tincompound, acidic phosphates, mixture or reaction product of the amineswith the acidic phosphates, saturated or unsaturated polyvalentcarboxylic acid or anhydride thereof, reactive silicone compound,organic titanate compounds, organic aluminum compounds, or a mixturethereof because of a high activity. Such the catalysts for curing(VII-C) may be employed solely or even in combination of two or morekinds.

Use amount of the catalysts for curing (VII-C) is not particularlylimited, and it is usually 0.1-20 parts, and preferably 1-10 parts basedon 100 parts of solid content of the component (VII-A) and the component(VII-B). In the case that the use amount of the components (VII-C) isless than 0.1 parts, curability tends to lower and, in the case ofexceeding 20 parts, physical properties (an outer appearance) in acoating layer tend to lower.

(D) Other Additives (VII-D)

In the composition of the present invention, a dehydrating agent may beoptionally added and, there can be ensured a stability, a stability notincluding any problems even though being repeatedly employed over a longtime of period by using the dehydrating agent.

As the dehydrating agent, for example, there are enumerated hydrolyzableester compounds such as ortho methylformate, ortho ethylformate, orthomethylacetate, ortho ethylacetate, methyltrimethoxy silane,γ-methacryloxypropyl trimethoxy silane, vinyltrimethoxy silane, methylsilicate, and ethyl silicate.

The above hydrolyzable ester compounds may be added beforepolymerization, after polymerization, and during polymerization of thecopolymer (VII-B) containing the alkoxysilyl group.

Use amount of the dehydrating agent is not particularly limited and, itis usually not more than 100 parts by weight, and preferably not morethan 50 parts by weight based on 100 parts by weight of solid componentsin the component (VII-A) and the component (VII-B).

Further, by simultaneously employing an accelerating agent for thedehydrating agent, an effect by the dehydrating agent can be elevated.

As the accelerating agent for the dehydrating agent, for example, thereare enumerated an inorganic acid such as hydrochloric acid, sulphuricacid, phosphoric acid, and sulphuric acid; an organic acid such asformic acid, acetic acid, oxalic acid, benzoic acid, phthalic acid,paratoluene sulphonic acid, acrylic acid, and methacrylic acid; a metalsalt od carboxylic acid such as an alkyl titanate and lead octylate; acarboxylic acid type organic tin compound such as tin octylate,dibutyltin dilaurate and dioctyltin dimaleate; a sulphide compound suchas monobutyltin sulphide and dioctyyltin mercaptide, and a mercaptidetype organic compound; an organic tin oxide such as dioctyltin oxide; anorganic tin compound by a reaction of the organic tin oxide with anester compound such as ethylsilicate, ethylsilicate 40, dimethylmaleateand dioctyl phthalate; an amine such as tetraethylene pentamine,triethylene diamine, and N-β-aminoethyl-γ-aminopropyl trimethoxy silane;an alkali catalyst such as potassium hydroxide and sodium hydroxide,etc., and the organic acid, inorganic acid and the organic tin compoundare preferred.

The accelerator for the dehydrating agent is employed in 0.0001-20 partsby weight, and preferably 0.001-10 parts by weight based on 100 parts byweight of the dehydrating agent. In the case of employing a compoundwhich is also the above-described component (VII-C) as the acceleratorfor the dehydrating agent, it is employed in use amount of the component(VII-C).

In the composition of the present invention, a solvent may be added and,nonreactive solvents are preferably employed.

As specific examples of such the solvents, for example, there areenumerated an aliphatic hydrocarbon solvent which is employed for ausual coating and a coating agent, aromatic hydrocarbons, chlorinatedhydrocarbons, alcohols, ketones, esters, ethers, alcohol esters, ketonealcohols, ether alcohols, ketone ethers, ketone esters, and esterethers, etc. Of those, in the case that there is employed a solventincluding an alkyl alcohol, a stability is preferably improved in thecomposition of the present invention.

As the alkyl alcohol, there is preferred an alcohol having a carbonnumber of 1-10 in the alkyl group and, for example, there are employedmethyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol,n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butylalcohol, n-amino alcohol, isoamyl alcohol, hexyl alcohol, octyl alcohol,and cellosolves, etc.

Use amount of the alcohols is not particularly limited, and it is notmore than 100 parts by weight, and preferably not more than 50 parts byweight based on 100 parts by weight of solid components of thecomponents (VII-A) and (VII-B).

By employing an alcohol, particularly, an alkyl alcohol together withthe dehydrating agent, there is observed a remarkable effect in astorage stability in the case that there are stored by mixing thecomponents (VII-A), (VII-B), and (VII-C) in the composition of thepresent invention.

Use amount of the solvents depends upon a molecular weight orcomposition of the components (VII-A) and (VII-B), and it is adjusted byfitting to a solid component concentration or viscosity to bepractically required.

In order to improve characteristics such as adhesion, hardness, andsolvent resistance, there may be even added a hydrolyzable silanecompound, a condensate thereof, a reaction product thereof, or a mixturethereof in the composition of the present invention.

As specific examples of the hydrolyzable silane compound, for example,there are enumerated methylsilicate, methyltrimethoxy silane,ethyltrimethoxy silane, butyltrimethoxy silane, octyltrimethoxy silane,dodecyltrimethoxy silane, phenyltrimethoxy silane, vinyltrimethoxysilane, γ-methacryloxypropyl trimethoxy silane, γ-acryloxypropyltrimethoxy silane, γ-glycidoxypropyl trimethoxy silane, γ-mercaptopropyltrimethoxy silane, γ-aminopropyl trimethoxy silane,N-β-aminoethyl-γ-propyl trimethoxy silane, dimethyldimethoxy silane,diethyldimethoxy silane, dibutyldimethoxy silane, diphenyldimethoxysilane, vinylmethyldimethoxy silane, γ-methacryloxyproyl methyldimethoxysilane, trimethylmethoxy silane, triethylmethoxy silane,triphenylmethoxy silane, ethyl silicate, methyltriethoxy silane,ethyltriethoxy silane, butyltriethoxy silane, octyltriethoxy silane,dodecyltriethoxy silane, phenyltriethoxy silane, vinyltriethoxy silane,γ-methacryloxyproyl triethoxy silane, γ-acryloxyproyl triethoxy silane,γ-glycidoxyproyl triethoxy silane, γ-mercaptopropyl triethoxy silane,γ-aminopropyl triethoxy silane, N-β-aminoethyl-γ-propyl triethoxysilane, dimethyl diethoxy silane, diethyl diethoxy silane, dibutyldiethoxy silane, diphenyl diethoxy silane, vinylmethyldiethoxy silane,γ-methacryloxyproyl methyldiethoxy silane, trimethylethoxy silane,triethylethoxy silane, and triphenylmethoxy silane, etc.

Further, a condensate such as a partially-hydrolyzed condensate of thesilane compounds can be readily obtained by the silane compounds solelyor in combination and adding necessary amount of water and, optionallyadding a small amount of catalysts for condensation such as hydrochloricacid and sulphuric acid, while maintaining at from an ordinarytemperature to 100° C., followed by proceeding while removing an alcoholproduced. For example, as a compound containing methoxysilyl group whichis a partially-hydrolyzed condensate of methyl silicate, there areenumerated Methyl Silicate 47, Methyl Silicate 51, Methyl Silicate 55,Methyl Silicate 58, and Methyl Silicate 60 manufactured by Nihon KolcoatKagaku, Ltd., etc.

As the compound containing methoxysilyl group which is apartially-hydrolyzed condensate of methyl trimethoxy silane and dimethyldimethoxy silane, there are enumerated AFP-1, AFP-2, AFP-6, KP213,KR217, and KR9218 manufactured by Shin-etsu Kagaku Kogyo, Ltd.: TSR165and TR3357 manufactured by Toshiba Silicone, Ltd.: Y-1587, FZ3701, andFZ3704 manufactured by Nihon Unicar, Ltd., etc.

Further, as the compound containing ethoxysilyl group which is apartially-hydrolyzed condensate of ethyl silicate, there are enumeratedEthyl Silicate 40, HAS-1, HAS-6, and HAS-10 manufactured by NihonKolcoat, Ltd., etc.

As the reaction product of the hydrolyzable silane compound, forexample, there are enumerated a reaction product of a silane couplingagent containing amino group with a compound containing an epoxy group,a reaction product of a silane coupling agent containing amino groupwith a silane coupling agent containing an epoxy group such asethyleneoxide, butyleneoxide, epichlorohydrin, an epoxidized soybeanoil, Epikote 828 and Epikote 1001 manufactured by Yuka Shell Epoxy,Ltd.; a reaction product of a silane coupling agent containing an epoxygroup with aliphatic amines such as ethyl amine, diethyl amine, triethylamine, ethylene diamine, hexane diamine, diethylene triamine,triethylene tetramine, and tetraethylene pentamine, aromatic amines suchas aniline and diphenyl amine, cycloaliphatic amines such as cyclopentylamine and cyclohexyl amine, amines such as ethanolamine, etc.

There is not particularly limited use amount of the hydrolyzable silanecompound, the condensate thereof, the reaction product thereof, and amixture thereof, and it is generally not more than 100 parts by weight,and preferably not more than 50 parts by weight based on 100 parts byweight of solid components of the components (VII-A) and (VII-B).

In the composition of the present invention, a polyorganosiloxane may beadded in order to give a water repellent property to a cured coatinglayer. The polyorganosiloxane, if it has a reactive functional group andis compatible with the hydroxyl group-contained polymer (VII-A) and thecomponent (VII-B), can be freely selected and is not particularlylimited.

Structure of the polyorganosiloxane may be in any of linear, branched,net-like, and cyclic in a structure and, as an organo group, there areenumerated hydrogen atom, an alkyl group, an alkenyl group, and an arylgroup, methyl group, ethyl group, propyl group, butyl group, hexylgroup, allyl group, and phenyl group, etc. Of the organo groups, methylgroup and phenyl group are practically advantageous because of beingindustrially prepared and low in price.

As the reactive functional groups, there are preferred a silanol group,an alkoxysilyl group, an alcoholic hydroxyl group, glycidyl group, aminogroup, mercapto group, carboxylic group, amide group, vinyl group, and(meth)acryloxy group and. Of those, the silanol group, the alkoxysilylgroup, and alcoholic hydroxyl group are preferred.

In the polyorganosiloxane, the number of the reactive functional groupsis preferably not less than 1 piece in one molecule. In thepolyorganosiloxane, although a molecular weight can be freely selectedif it is a range having compatibility, since compatibility lowers in ahigher molecular weight, silicone atom is preferred in 2-300 pieces, andit is more preferred in 2-100 pieces, and it is particularly preferredin 3-50 pieces.

As a specific example of such the polyorganosiloxane, for example, thereare enumerated a silicone rubber, a silicone varnish, a reactivepolydimethylsiloxane employed as an intermediate for modifying anorganic polymer and a reactive silicone oil, and a reactive polydiphenylsiloxane, a reactive polymethylphenyl siloxane, which is a copolymerizedtype of dimethyl with diphenyl,

(in the formula, R is a group selected from the group consisting of aphenyl group, an alkyl group having a carbon number of 1-4, and hydroxylgroup),

(in the formula, R is a group selected from the group consisting of aphenyl group, an alkyl group having a carbon number of 1-4, and hydroxylgroup, and l, m, and n are 1-5, respectively),

Use amount of the polyorganosiloxane is generally not less than 100parts, and preferably not less than 50 parts based on 100 parts of solidcomponents in the components (VII-A) and (VII-B).

In the composition of the present invention, there may be even addedadditives such as a diluent, pigments (including an extender pigment),an ultraviolet ray absorbent, an anti-sedimentation agent, a levelingagent; celluloses such as a nitrocellulose, and a cellulose acetatebutylate; and a resin such as an epoxy resin, a melamine resin, avinylchloride resin, a chlorinated polyolefin, a chlorinated rubber, apolyvinyl butylal, an alkyd resin, an oil-free alkyd resin, anacrylic-modified alkyd resin, an acrylic resin, a fluorine resin havinghydroxyl group, a polyester polyol, a polyether polyol, and apolyurethane polyol, etc.

Hereinafter, there is illustrated a method for the preparation of thecomposition in relation to the present invention.

The composition of the present invention is composed of theabove-described components is not particularly limited, for example, itis prepared by cold-blending of the components (VII-A) and (VII-B), ormixing the components (VII-A) and (VII-B) and after that, heating(hot-blending) to obtain a partially reacted product, and mixing theproduct with the component (VII-C).

The composition of the present invention can be cured by heating at notless than 30° C., and preferably 55-35° C. after coating on a body to becoated by usual methods using, for example, dipping, spraying, brushing,and a roll coating or a flow coater.

The thermosetting composition of the present invention is useful as acoating, an adhesive, a sealant, and a modifier for plastics, and in thecase of employing as the coating, it can provide a coating layer whichis excellent in weatherability, adhesion, and hardness and, moreover,which is excellent in durability.

Hereinafter, a coated body of the present invention will be illustrated.

In the coated body of the present invention, there is coated a coatingcontaining metallic powder and/or coloring pigments (a coatingcontaining the metallic powder is called a metallic base coating, and acoating containing the coloring pigments is called a solid colorcoating), and since a top clear coating (a thermosetting coating)primarily containing the above-described the thermosetting compositionis coated on a coated surface, it is a coated body which is excellent inweatherability, acid resistance, and staining resistance, etc.

The coating containing metallic powder and/or coloring pigments is notparticularly limited and, for example, there are enumerated compoundsprimarily containing an amino alkyd resin, an oil-free alkyd resin, athermosetting acrylic resin, a thermosetting urethane resin, anitrocellulose lacquer, a modified acrylic lacquer, a straight acryliclacquer, a ordinary temperature-curable urethane resin, an acrylicenamel resin, an oxidation-curable modified alkyd resin (CAB, etc.), anordinary temperature- or thermally-curable type fluorine resin, a resincontaining a hydrolyzable silyl group, and a mixture of a resincontaining a hydrolyzable silyl group with a vinyl-based copolymerhaving hydroxylic group, etc.

Further, as a type of the coating, there may be even any one of asolution type coating containing an organic solvent as a medium, anonaqueous dispersion coating, a multi-liquid type coating, a powdercoating, a slurry coating, and a water-based coating, etc.

The above-described metallic powder and coloring pigments may be evenpublicly-known, and there may be even any one of metallic powder andcoloring pigments.

As the metallic powder, for example, there are enumerated aluminumpowder, copper powder, and mica powder, etc., and, as the coloringpigments, for example, there are enumerated organic-based pigments suchas Phthalocyanine Blue, Toluidine Red, and Benzidine Yellow, andinorganic-based pigments such as titanium oxide, carbon black, and ironoxide red, etc. The metallic powder and coloring pigments may beemployed solely or in combination of two or more kinds.

In the coating containing the metallic powder and/or coloring pigments,weatherability can be more improved by employing an ultraviolet rayabsorbent and a photostabilizer.

As the ultraviolet ray absorbent, conventionally-known ones can bewidely employed, for example, there is preferred an ultraviolet rayabsorbent such as a benzophenone-based one, a triazole-based one, aphenylsalicylate-based one, a diphenylacrylate-based one, and anacetophenone-based one.

As the photostabilizer, conventionally-known ones can be widelyemployed, for example, there are enumeratedbis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,2-(3,5-di-tert-butyl-4-hydroxybenzyl)2-n-butyl maloatebis(1,2,2,6,6-pentamethyl-4-piperidyl),tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, andtetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, etc. These may be employed solely or even incombination of two or more kinds.

In the coating containing the metallic powder and/or coloring pigments,there may be even added the above-described silane compounds,condensates thereof, reaction product thereof, and a mixture thereof inorder to elevate adhesion to a coating layer and a top clear coatinglayer.

Addition amount thereof is usually not more than 50 parts, andpreferably not more than 20 parts in 100 parts of the coating containingthe metallic powder and/or coloring pigments.

By formulating the above-described ultraviolet ray absorbent orphotostabilizer with the top clear coating, weatherability is remarkablyimproved. Further, weatherability can be more improved by employing theultraviolet ray absorbent together with the photostabilizer.

The formulating amount of the ultraviolet ray absorbent is usually0.1-10 parts, and preferably 1-5 parts based on 100 parts of solidcomponents in the top clear coating. Further, the formulating amount ofthe photostabilizer is usually 0.1-10 parts, and preferably 1-5 partsbased on 100 parts of solid components in the top clear coating.

A method for the preparation of the body to be coated of the presentinvention is not particularly limited and, for example, it can beprepared by a method (two coat-one bake style) in which after coatingthe coating containing the metallic powder and/or coloring pigments andsetting for several minutes, the top clear coating is coated by awet-on-wet style, followed by thermally curing, and a method (twocoat-two bake style) in which after coating the coating containing themetallic powder and/or coloring pigments and thermally curing, the topclear coating is coated and thermally cured.

Thickness of a coating layer is not also particularly limited and,thickness of a coating layer containing the metallic powder (or)coloring pigments is preferably 10-30 μm from a viewpoint of concealing,and thickness of the top clear coat is preferably 20-50 μm from aviewpoint of durability.

Thus-prepared coating layer shows an excellent property in a specificcharacteristic such as outer appearance and weatherability.

As an object for forming the coating layer, for example, there areenumerated buildings, cars, industrial machines, steel-made furniture,home electric appliances, and plastics products, etc., and the coatingis employed for finishing as an over coating.

Hereinafter, the present invention No. VIII is illustrated.

The hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactone in which a proportion of monomers having two or morecontinuous chains (n≧2) of lactone represented by the above-describedgeneral formula (I) to be employed in the present invention is less than50% is as illustrated in the present invention No. I.

By allowing to react the hydroxyalkyl(meth)acrylate composition (a)modified by a small amount of lactone represented by the above-describedgeneral formula (I) with the carboxylic acid represented by theabove-described general formula (VIII-2) or the anhydride thereof(VIII-b), there is obtained the hydroxyalkyl(meth)acrylate composition(a′) having carboxylic group modified by a small amount of lactonerepresented by the above-described general formula (VIII-3).

As the carboxylic acid represented by the general formula (VIII-2) orthe anhydride thereof (VIII-b), for example, there can be enumeratedmalonic acid, succinic acid, glutaric acid, adipic acid, sberic acid,azelaic acid, sebasic acid, brasilic acid, maleic acid, fumaric acid,itaconic acid, phthalic acid, isophthalic acid, terephthalic acid,trimerritic acid, tartaric acid, malic acid, mannose acid,1,4-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid,1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid,hexahydrophthalic acid, galactose acid, 4,5-cyclohexene dicarboxylicacid, 3,6-methylene-4-cyclohexene-1,2-dicarboxylic acid, citric acid,pyromellitic acid, dimer of phthalic anhydride, diphenylethertetracarboxylic acid, diphenylsulphone tetracarboxylic acid,benzophenone tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid,anhydrides thereof, and a mixture thereof. Of those, maleic anhydride,phthalic anhydride, trimerritic anhydride, and pyromerritic anhydrideare preferred as a raw material for the present invention because ofreadily obtaining.

The carboxylic acid may be unsubstituted or can be also substituted byoptional groups by which a reaction is not significantly disturbed.Examples of appropriate substituent groups include a halogen, nitro,alkoxy, alkyl, and carbonyl group, etc. Further, a desired product canbe prepared by allowing to react an acid chloride which is the component(VIII-b) with a lactone(meth)acrylate.

Otherwise, residual carboxylic group (R⁹ in the general formula(VIII-2)) of the acid anhydride may contain an inert functional groupsuch as ether, ester, halogen, and ketone, and, for example, there canbe employed an ethyleneglycol ester of trimellitic anhydride (RicacidTMEG™ (manufactured by Shinnihon Rika)) represented by general formula(4) described below, etc.

By employing an anhydride of a polyvalent carboxylic having at least twocarboxylic groups in the molecule, since one carboxylic group of thepolyvalent carboxylic acid qualitatively reacts with hydroxyl group atterminal of the hydroxyalkyl (meth)acrylate composition (a) modified bya small amount of lactone, one carboxylic group of the polyvalentcarboxylic acid can be controlled so as to add to hydroxyl group at aterminal group.

As a result, there can become obtained the (meth)acrylate compound (a′,VIII-3) containing at least one carboxylic group in the molecule in ahigh selectivity.

A reaction of the above-described component (a) with the component(VIII-b) slowly proceeds at a low temperature and, a polymerization of(meth)acryloyl group is caused at a high temperature. Accordingly, apreferred temperature ranges in 40-160° C.

In order to prevent the polymerization of (meth)acryloyl group, thereaction is preferably conducted under the presence of oxygen and,further, it is preferably conducted under the presence of, for example,a polymerization inhibitor such as hydroquinone monomethylether. Thepolymerization inhibitor such as quinones is employed in an amount ofnot more than 5,000 ppm, and preferably not more than 700 ppm in areaction mass.

Although the reaction proceeds under the absence of a catalyst, thecatalyst may be even optionally employed. As the catalyst, there areenumerated a basic compound such as triethylamine, pyridine,N-methylimidazole, diazabicycloundecene, and diazabicyclooctane; anammonium salt such as trimethylbenzyl ammonium chloride and tetrabutylammonium bromide; and a publicly-known catalyst such as other acids andalkalis, etc.

Although the reaction may be conducted under the absence of a solvent,the solvent may be even employed. As the solvent, there are enumeratedtoluene, methylethyl ketone, ethyl acetate, and1-methoxy-2-acetoxypropane, etc. Further, there may be employed areactive diluent such as a polyethyleneglycol monomethylethermono(meth)acrylate or a polyethyleneglycol di(meth)acrylate which are amono or poly(meth)acrylate.

Feeding ratio of the hydroxyalkyl(meth)acrylate composition (a) modifiedby a small amount of lactone with the carboxylic acid or the anhydride(VIII-b) is preferably 0.9-1.1 by mol. In the case that molar ratio ofthe component (VIII-b) exceeds 1.1, there remains a large amount of thecomponent (VIII-b) and, in uses in which an epoxy compound isformulated, a pot-life is unpreferably shortened. Further, in the caseof less than 0.9, a high molecular weight diesters or triesters, etc.are by-produced, unpreferably resulting in that a viscosity becomeshigh.

Method for the preparation according to the present invention can beadvantageously conducted by industrial fashion and, moreover, a lactoneacrylate compound having carboxylic group obtained is effective forimprovement of adhesion to materials such as a resin having amino groupswhich includes a nylon, an inorganic compound which includes a metal andsilica having hydroxyl group and, further, it is exceedingly useful as araw material for resins, which is effective for solubility of an acrylicresin to water and an aqueous alkali solution, above all, for shorteninga developing time of period in an alkali development step when preparinga pattern in which curing by an ultraviolet ray is utilized, and for aremoval property of an uncured portion.

Subsequently, the present invention No. IX is illustrated hereinafter indetail.

I. Raw Material for a Curable Resin Composition

First of all, there are illustrated raw materials to be employed forpreparation of the curable resin composition in relation to the presentinvention.

I-1. <Acrylic Polycarboxylic Acid Resin (A′)>

The acrylic polycarboxylic acid resin (A′) to be employed for thecurable resin composition of the present invention has at least twocarboxylic groups on average, 5-300 mgKOH/g of an acid value, andpreferably 25-250 mgKOH/g, more preferably 50-200 mgKOH/g, 500-8000 of anumber average molecular weight, preferably 800-6000, and morepreferably 1500-4000.

The acrylic polycarboxylic acid resin (A′) is obtained by copolymerizing5-80% by weight of an ethylenic unsaturated monomer having carboxylicgroup (a1), provided that a ratio of the hydroxyalkyl(meth)acrylatecomposition (a′) having carboxylic group modified by a small amount oflactone is 5-50% by weight in the ethylenic unsaturated monomer havingcarboxylic group (a1), with 20-95% by weight of an ethylenic unsaturatedmonomer not having carboxylic group (a2) according to publicly-knownmethods.

In the case that the monomer (a′) is less than 5% by weight, a coatinglayer becomes unpreferably hard and, in the case of exceeding 50% byweight, water resistance becomes unpreferably worse.

Further, in the case that the monomer (a1) exceeds 80% by weight, acoating layer becomes unpreferably hard and brittle, and in the casethat the monomer (a2) exceeds 95% by weight, curing becomes unpreferablyinsufficient.

Proportion of the monomer (a′) which constructs the acrylicpolycarboxylic acid resin (A′) is 5-50% by weight, and preferably 10-40%by weight.

Copolymerization can be conducted using an azo-based radical initiatoror a peroxide-based initiator as a radical polymerization initiator inan amount of 0.5-15 parts by weight based on 100 parts by weight oftotal monomers, and at a polymerization temperature of 80-200° C. and apolymerization period of 3-10 hours, and under an ordinary pressure orcompressurization. In the case, there may be even added a chain transferagent and an agent for preventing discoloration, etc.

Further, in the present invention, there may be even employed an acrylicpolycarboxylic acid resin (bA′) in which terminal carboxylic groups inthe acrylic polycarboxylic acid resin (A′) are blocked by a block groupwhich produces carboxylic group by heating and/or water, in place of theacrylic polycarboxylic acid resin (A′).

I-1-1 <Hydroxyalkyl(meth)acrylate Composition (a′) having CarboxylicGroup Modified by a Small Amount of Lactone>

The hydroxyalkyl(meth)acrylate composition (a′) having carboxylic groupmodified by a small amount of lactone to be employed for the acrylicpolycarboxylic acid resin (A′) is a composition obtained by allowing toreact the hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactone represented by the above-described general formula (1)with the carboxylic acid represented by the above-described generalformula (VIII-2) or the anhydride thereof (VIII-b), and the compositionis represented by the above-described general formula (VIII-3).

(1) <Hydroxyalkyl(meth)acrylate Composition (a) Modified by a SmallAmount of Lactone>

The hydroxyalkyl(meth)acrylate composition (a) modified by a smallamount of lactone represented by the above-described general formula (1)is as illustrated in the present invention No. I.

(2) <Carboxylic Acid or Anhydride Thereof>

The carboxylic acid represented by the above-described general formula(VIII-2) or the anhydride thereof is as illustrated in the presentinvention No. VIII.

For example, there can be enumerated malonic acid, succinic acid,glutaric acid, adipic acid, sberic acid, azelaic acid, sebasic acid,brasilic acid, maleic acid, fumaric acid, itaconic acid, phthalic acid,isophthalic acid, terephthalic acid, trimerritic acid, tartaric acid,malic acid, mannose acid, 1,4-cyclohexane dicarboxylic acid,1,2-cyclohexane dicarboxylic acid,1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid,hexahydrophthalic acid, galactose acid, 4,5-cyclohexene dicarboxylicacid, 3,6-methylene-4-cyclohexene-1,2-dicarboxylic acid, citric acid,pyromerritic acid, dimer of phthalic anhydride, diphenylethertetracarboxylic acid, diphenylsulphone tetracarboxylic acid,benzophenone tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid,anhydrides thereof, and a mixture thereof. Of those, maleic anhydride,phthalic anhydride, trimellitic anhydride, and pyromellitic anhydrideare preferred as a raw material for the present invention because ofreadily obtaining.

The carboxylic acid may be unsubstituted or can be also substituted byoptional groups by which a reaction is not significantly disturbed.Examples of appropriate substituent groups include a halogen, nitro,alkoxy, alkyl, and carbonyl group, etc. Further, a desired product canbe prepared by allowing to react an acid chloride with alactone(meth)acrylate.

Otherwise, residual carboxylic group (R⁶ in the general formula (2)) inthe acid anhydride may even contain an inert functional group such asether, ester, halogen, and ketone, and, for example, there can beemployed an ethyleneglycol ester of trimerritic anhydride (Ricacid TMEG™(manufactured by Shinnihon Rika)), etc.

By employing an anhydride of a polyvalent carboxylic acid having atleast two carboxylic groups in the molecule, since one carboxylic groupin the polyvalent carboxylic acid qualitatively reacts with hydroxylgroup at a terminal of the hydroxyalkyl (meth)acrylate composition (a)modified by a small amount of lactone, one carboxylic group of thepolyvalent carboxylic acid can be controlled so as to add to hydroxylgroup at a terminal group.

As a result, the hydroxyalkyl(meth)acrylate composition (a′) modified bylactone containing carboxylic group can become obtained in a highefficiency.

A reaction of the above-described component (a) with the carboxylic acidor the anhydride thereof slowly proceeds at a low temperature and, apolymerization of (meth)acryloyl group is caused at a high temperature.Accordingly, a preferred temperature ranges in 40-160° C.

In order to prevent the polymerization of (meth)acryloyl group, thereaction is preferably conducted under the presence of oxygen and, it ispreferably conducted under the presence of, for example, apolymerization inhibitor such as hydroquinone monomethylether. Thepolymerization inhibitor such as quinones is employed in an amount ofnot more than 5,000 ppm, and preferably not more than 700 ppm in areaction mass.

Although the reaction proceeds under the absence of a catalyst, thecatalyst may be even optionally employed. As the catalyst, there areenumerated a basic compound such as triethylamine, pyridine,N-methylimidazole, diazabicycloundecene, and diazabicyclooctane; anammonium salt such as trimethylbenzyl ammonium chloride and tetrabutylammonium bromide; and a publicly-known catalyst such as other acids andalkalis, etc.

The reaction may be conduct under the absence of a solvent and, thesolvent may be even employed. As the solvent, there are enumeratedtoluene, methylethyl ketone, ethyl acetate, and1-methoxy-2-acetoxypropane, etc. Further, there may be employed areactive diluent such as a polyethyleneglycol monomethylethermono(meth)acrylate or a polyethyleneglycol di(meth)acrylate which are amono or poly(meth)acrylate as a solvent.

Feeding ratio of the hydroxyalkyl(meth)acrylate composition (a) modifiedby a small amount of lactone with the carboxylic acid or the anhydrideis preferably 0.9-1.1 by mol. In the case that molar ratio of thecarboxylic acid or the anhydride exceeds 1.1, residual amount thereofbecomes large and, in uses in which an epoxy compound is formulated, apot-life is unpreferably shortened.

Further, in the case of less than 0.9, high molecular weight diesters ortriesters, etc. are by-produced, unpreferably resulting in that aviscosity becomes high.

I-1-2. <Ethylenic Unsaturated Monomer (a1) having Carboxylic Group>

As the ethylenic unsaturated monomer (a1) having carboxylic group whichis other monomer component to be employed for copolymerization of theabove-described acrylic polycarboxylic acid resin (A′), for example,there are enumerated acrylic acid, methacrylic acid, itaconic acid,maleic acid, and an adduct of ε-caprolactone therewith (for example,“Alonix M-5300” manufactured by Toa Gosei Kagaku, Ltd.), an adduct ofthe ethylenic unsaturated monomer (d3) having hydroxyl group representedby the above-described general formula (4) with the carboxylic acid orthe anhydride, and an adduct of an ethylenic unsaturated monomer (f)having an acid anhydride group with a monoalcohol (g). These may beemployed solely or in combination of two or more kinds.

The carboxylic acid or the anhydride to be employed herein, if it is acompound capable of providing a carboxylic functional property by a halfesterification reaction with hydroxyl group at ordinary conditions suchas a room temperature to 150° C. and an ordinary pressure, is notparticularly limited. Herein, there is preferably employed a compoundcontaining an acid anhydride group having a cyclic (unsaturated orsaturated) group having a carbon number of 8-12, particularly, 8-10. Bythe use of such the compound, compatibility becomes excellent in a resinobtained.

As the acid anhydride, there can be employed an anhydride of thecarboxylic acid described in the above-described I-1-1 (2) and,preferably, there are enumerated phthalic anhydride, tetrahydrophthalicanhydride, hexahydrophthalic anhydride, 4-methyl hexahydrophthalicanhydride, and trimellitic anhydride, etc.

As specific examples of the ethylenic unsaturated monomer (f) having anacid anhydride group to be employed herein, there are enumerateditaconic anhydride, maleic anhydride, and cytraconic anhydride, etc.

As specific examples of the monoalcohol (g) to be employed herein, thereare enumerated methanol, ethanol, n-propanol, i-propanol, n-butanol,i-butanol, t-butanol, n-hexylalcohol, lauryl alcohol, methylcellosolve,ethylcellosolve, methoxypropanol, ethoxypropanol, fulfuryl alcohol,dimethylaminoethanol, acetol, allyl alcohol, and propalgyl alcohol, etc.

I-1-3. <Ethylenic Unsaturated Monomer (a2) not having Carboxylic Group>

As specific examples of the ethylenic unsaturated monomer (a2) nothaving carboxylic group which is another monomer component to beemployed for the copolymerization of the acrylic polycarboxylic acidresin (A′), for example, there are enumerated styrene, α-methylstyrene,p-t-butylylstyrene, (meth)acrylate (for example, methyl(meth)acrylate,ethyl(meth)acrylate, propyl(meth)acrylate, n-, i-, andt-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate andlauryl(meth)acrylate, cyclohexyl(meth)acrylate, andisobonyl(meth)acrylate, etc.), Veova-9 and Veova-10 manufactured byShell, AG.

In the case that styrene and a styrene derivative are employed as theethylenic unsaturated monomer (a2) not having carboxylic groups, thoseare preferably employed in an amount of 5-40% by weight.

I-2. <Acrylic Polycarboxylic Acid Resin (A*′) having Carboxylic Groupsand Carboxylate Groups>

As the acrylic polycarboxylic acid resin (A′) to be employed for thecurable resin composition of the present invention, the acrylicpolycarboxylic acid resin (A*′) having carboxylic groups and carboxylategroups is preferably employed, whereby, acid resistance is improved in acoating a composition obtained.

The acrylic polycarboxylic acid resin (A*′) having carboxylic groups andcarboxylate groups is obtained by allowing to react 5-50% by weight ofthe hydroxyalkyl(meth)acrylate composition having carboxylic groups (a′)modified by a small amount of lactones and 5-50% by weight of theacrylic polyacid anhydride (a3) with 5-50% by weight of the monoalcohols(g).

As proportion of the monomer (a′) which constructs the acrylicpolycarboxylic acid resin (A*′) having carboxylic groups and carboxylategroups, it is preferably 5-50% by weight, and more preferably 10-40% byweight.

In the case that the monomer (a′) is less than 5% by weight, a coatinglayer unpreferably becomes hard and, in the case of exceeding 50% byweight, water resistance unpreferably becomes worse.

Further, in the case that the (3₃) exceeds 50% by weight, unreactedanhydride groups are remained and, resulting in that a storage stabilitybecomes unpreferably worse and, in the case of less than 5% by weight,the monoalcohols (g) are excessively remained, unpreferably resulting inthat lack of curing is caused in curing.

The acrylic polyacid anhydride (a3) is obtained by allowing tocopolymerize 15-40% by weight, and preferably 15-35% by weight of theethylenic unsaturated monomer (f) having an acid anhydride group with60-85% by weight, and preferably 65-85% by weight of the ethylenicunsaturated monomer (d1) not having an acid anhydride group.

In the case that the amount of the ethylenic unsaturated monomer (f)having an acid anhydride group is less than 15% by weight, curabilitybecomes short and, in the case of exceeding 40% by weight, a coatinglayer becomes excessively brittle, resulting in that weatherabilitybecomes short. As specific examples of ethylenic unsaturated monomer (f)having an acid anhydride group, there are enumerated ones alreadyillustrated.

The ethylenic unsaturated monomer (d1) not having an acid anhydridegroup, if it does not adversely affect to the acid anhydride group, isnot particularly limited, and there is preferred a monomer having acarbon number of 3-15, particularly, 3-12 and having one ethylenicunsaturated bond.

A mixture of at least two ethylenic unsaturated monomers can be alsoemployed as the ethylenic unsaturated monomer (d1) not having an acidanhydride group. Because, it is effective for elevating a compatibilityof resins themselves. Specifically, the above-described monomers areenumerated as the ethylenic unsaturated monomer (a2) not havingcarboxylic group. Monomers having carboxylic group such as acrylic acid,methacrylic acid, itaconic acid, and maleic acid can be employed as theethylenic unsaturated monomer (d1) not having an acid anhydride group.Of those, scratch resistance in a coating layer is particularlypreferably elevated by the use of a long chain carboxylic acid monomerhaving a spacer portion of carbon number of 5-20 pieces or so between anethylenic unsaturated group and carboxylic group such as an adductthereof with ε-caprolactone (for example, Alonix M-5300).

For example, as the ethylenic unsaturated monomer (d1) not having anacid anhydride group, there can be also employed an ethylenicunsaturated monomer (d2) having carboxylic group obtained byhalf-esterification reaction of the ethylenic unsaturated monomer (d3)having hydroxyl group with a compound having an acid anhydride group in1/0.5-1/1.0, preferably, 1/0.8-1/1.0 of a molar ratio of hydroxyl groupwith respect to the acid anhydride group. In the case that the molarratio is not less than 1/0.5, viscosity becomes high and workabilitybecomes worse. In the case of not more than 1/1.0, an excessive acidanhydride is remained, and water resistance becomes worse in a coatinglayer.

In the ethylenic unsaturated monomer (d3) having hydroxyl group to beemployed herein, a carbon number is preferably 2-40, and more preferably4-20. In the case that a chain length is too short, flexibility is lostin the vicinity of crosslinking points, resulting in that a coatinglayer becomes too hard and, in the case that it is too long, a molecularweight becomes too large between crosslinking points.

In general, there is enumerated the ethylenic unsaturated monomer (d3)having hydroxyl group which has an organic chain shown by theabove-described general formula (4) or an organic chain shown by theabove-described general formula (6).

Specifically, there are enumerated 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl (meth)acrylate,4-hydroxybutyl(meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and areaction product thereof with ε-caprolactone and, a compound which canbe prepared by esterification of a (meth)acrylic acid with a largelyexcessive diol (for example, 1,4-butane diol, 1,6-hexane diol, apolyethylene glycol, and a polypropylene glycol).

Such the compounds are commercially supplied, for example,4-hydroxybutyl acrylate “4-HBA” and 4-hydroxybutylmethacrylate “4-HBMA”manufactured by Mitsubishi Kasei, Ltd., etc., and “Placcel FM1” and“Placcel FA1” manufactured by Daicel Chemical Industries, Ltd., etc. Asa propylene oxide-based monomer, there are “Blemmer PP-1000” and“Blemmer PP-800” manufactured by Nihon Yushi, Ltd., and as an ethyleneoxide-based monomer, there is “Blemmer PE-90” manufactured by NihonYushi, Ltd. As specific examples of the compound having an acidanhydride group, there are enumerated already exemplified ones.

The half esterification reaction of the ethylenic unsaturated monomer(d3) having hydroxyl group with the compound having an acid anhydridegroup is conducted according to usual methods, and it is conducted at atemperature of room temperature to 150° C.

Copolymerization of the ethylenic unsaturated monomer (f) having an acidanhydride croup with the ethylenic unsaturated monomer (d1) not havingan acid anhydride group is conducted, for example, by a publicly-knownmethod such as a solution polymerization which includes a radicalpolymerization. For example, it can be conducted at a polymerizationtemperature of 100-200° C. under an ordinary pressure orcompressurization for a polymerization time of period of 3-8 hours.

As an initiator, there is preferably employed an azo-based orperoxide-based initiator. There can be also employed other additivessuch as a chain transfer agent.

In the acrylic polyacid anhydride (a3) obtained, a number averagemolecular weight is 500-8000, further, 800-6000, particularly preferably1500-4000. In the case that the number average molecular weight exceeds8000, there lower compatibility of resins themselves and an outerappearance. In the case that the number average molecular weight is lessthan 500, curability becomes insufficient in a coating composition. Theacrylic polyacid anhydride (a3) obtained has at least two, preferably2-15 pieces of acid anhydride groups on an average in one molecule. Inthe case that the acid anhydride groups are less than 2 pieces in onemolecule, curability becomes insufficient in a coating composition. Inthe case of exceeding 15 pieces, a coating layer becomes hard and toobrittle and, weatherability is short.

Subsequently, the acrylic polycarboxylic acid resin (A*′) havingcarboxylic groups and carboxylate groups is prepared by allowing toreact the hydroxyalkyl(meth)acrylate composition having carboxylicgroups (a′) modified by a small amount of lactones and the acrylicpolyacid anhydride (a3) with the monoalcohol (g) in an amount of molarratio of the acid anhydride group with respect to hydroxyl group of1/10-1/1, preferably 1/5-1/1, and more preferably 1/2.0-1/1. In the caseof being less than 1/10, an excessive amount of the monoalcohol isremained, and there is caused lack of curing and, in the case ofexceeding 1/1, unreacted acid anhydride groups are remained, and storagestability becomes worse.

The monoalcohol (g) to be employed in the present invention haspreferably 1-12 pieces, particularly, 1-8 pieces of carbon numbers,because an alcohol evaporates to excellently reproduce the acidanhydride group by heating. As preferred specific examples of themonoalcohol to be employed, there are enumerated already exemplifiedones. There are particularly preferred acetol, fulfuryl alcohol, allylalcohol, propagyl alcohol, and methanol.

The acrylic polycarboxylic acid resin (A*′) having carboxylic groups andcarboxylate groups obtained has an acid value of 5-300 mgKOH/g, andpreferably 50-250 mgKOH/g. In the case that the acid value is less than5 mgKOH/g, curability becomes short and, in the case of exceeding 300mgKOH/g, storage stability unpreferably becomes short.

The acrylic polycarboxylic acid resin (A*′) component can be formulatedwith the curable resin composition in an amount of 10-70% by weight,preferably 15-50% by weight, and more preferably 20-45% by weight basedon total solid components in the curable resin composition. In the casethat formulating amount of the acrylic polycarboxylic acid resin (A*′)component is less than 10% by weight, acid resistance lowers in acoating layer obtained and, in the case of exceeding 70% by weight, thecoating layer becomes too hard.

I-3. <Acrylic Polycarboxylic Acid Resin (bA′) in which Carboxylic Groupsare Blocked>

In the curable resin composition of the present invention, the acrylicpolycarboxylic acid resin (bA′) in which carboxylic groups are blockedcan be employed in place of the acrylic polycarboxylic acid resin (A′).

The acrylic polycarboxylic acid resin (bA′) in which carboxylic groupsare blocked to be employed in the present invention, if it is an acrylicpolycarboxylic acid resin having carboxylic groups which are blocked bya blocking group which produces carboxylic group by heat and/or water(for example, moisture in atmosphere or water), can be employed withoutbeing particularly limited.

Such the blocked carboxylic group is shown by —COO—Z (Z is a blockedgroup derived from a blocking agent connected to hydroxyl group incarboxylic group).

As the Z, there can be preferably exemplified a silyl blocking group(K₁) or a vinylether blocking group (K₂) described below.

As the silyl blocking group (K₁), there can be exemplified a silylblocking group represented by the following general formula (7).

In the above formula (7), R¹-R³ are independently an alkyl group or arylgroup. As the alkyl group, there is enumerated a linear or branchedlower alkyl group having a carbon atom number of 1-10 and, for example,there are particularly preferred methyl group, ethyl group, propylgroup, butyl group, s-butyl group, t-butyl group, pentyl, and hexylgroup. As the aryl group, there is enumerated phenyl group, naphtylgroup, and indenyl group, etc. which may even have substituent groups,and phenyl group is particularly preferred.

As the silyl blocking group (K₁) represented by the general formula (7),there are enumerated trimethyl silyl group, diethyl methylsilyl group,ethyldimethyl silyl group, butyldimethyl silyl group, butylmethylethylsilyl group, phenyldimethyl silyl group, phenyldiethyl silyl group,diphenylmethyl silyl group, and diphenylethyl silyl group, etc.Particularly, in the R¹-R³ having smaller molecular weight, blockinggroup is readily unfastened, and preferably reactive.

As such blocking agents which produce such the silyl blocking group(K₁), a halogenated silane can be preferably employed. As halogenscontained in the halogenated silane, there are enumerated chlorine atomor bromine atom, etc.

As specific blocking agents, for example, there are enumerated trimethylsilyl chloride, diethylmethyl silyl chloride, ethyldimethyl silylchloride, butyldimethyl silyl bromide, and butylmethylethyl silylbromide, etc.

As the vinylether blocking group (K₂), there is exemplified thefollowing vinylether blocking group shown by formula (8) describedbelow.

In the above formula (8), R¹-R³ are independently a hydrogen atom or ahydrocarbon group having a carbon atom number of 1-18. R⁴ is ahydrocarbon group having a carbon atom number of 1-18. Y is an oxygenatom or sulphur atom. Further, R³ and R⁴ may be mutually connected, andthere may be formed a heterocyclic ring containing the Y as a heteroatom.

As the hydrocarbon atom in the above formula, there are enumerated analkyl group, a cycloalkyl group, and an aryl group.

As the alkyl group, for example, there is particularly preferred a loweralkyl group having a carbon atom number of 1-8 such as methyl group,ethyl group, propyl group, butyl group, s-butyl group, t-butyl group,pentyl group, and hexyl group. As the cycloalkyl group, for example,there are enumerated cyclopentyl group and cyclohexyl group, etc. As thearyl group, there are included phenyl group, naphtyl group, andanthrathene group, etc. which may have a substituent group, and phenylgroup is particularly preferred.

Such the vinylether blocking group (K₂) can be formed by allowing toreact an aliphatic vinylether or thioether, or a cyclic vinylether, orthioether with hydroxyl group in carboxylic group.

As the aliphatic vinylether, for example, there are enumeratedmethylvinylether, ethylvinylether, isopropyl vinylether,n-propylvinylether, isobutylvinylether, 2-ethylhexylvinylether,cyclohexylvinylether, or a vinylthioether corresponding thereto.

As the cyclic vinylether, for example, there are enumerated2,3-dihydrofran, 3,4-dihydrofran, 2,3-dihydro-2H-pyran,3,4-dihydro-2H-pyran, 3,4-dihydro-2-methoxy-2H-pyran,3,4-dihydro-4,4′-dimethyl-2H-pyran-2-on, 3,4-dihydro-2-ethoxy-2H-pyran,and 3,4-dihydro-2H-pyran-2-sodium carboxylate, etc.

As an epoxy group which is a second functional group, a nonalicyclicepoxy group and an alicyclic epoxy group are included.

As the nonalicyclic epoxy group, for example, there is exemplified agroup in which an epoxy bond by oxygen atom is formed between carbonatoms in an alkyl group such as 1,2-epoxy group and 1,3-epoxy group. Asthe alicyclic epoxy group, for example, there is exemplified a group inwhich oxygen atom forms an epoxy bond between carbon atoms which areadjacent to a ring in a 5- or 6-membered ring (there is also included ahydrocarbon having a bridge). Of those, the nonalicyclic epoxy group ismore preferably employed than the alicyclic epoxy group in a practicaluse.

In resins to be employed in the present invention, the above-describedfirst and second functional groups may even exist in an identical resin,or in individual resins, respectively. Carboxylic group produces asecondary hydroxyl group in addition to the formation of an ester bondby reacting with an epoxy group.

Further, a blocked carboxylic group produces a free carboxylic group bydisconnection of a blocked group, and the same reaction is caused as theabove descriptions. In the curable resin composition of the presentinvention, a crosslinking (curing) reaction is caused and a resin isformed by a mutual reaction in such the functional groups.

I-4. <Polyepoxide (IX-B)>

Polyepoxide (IX-B) which is another constructing component in thecurable resin composition of the present invention, if it is a compoundhaving at least two pieces of epoxy groups on an average in themolecule, preferably 2-10 pieces, and more preferably 3-8 pieces, is notparticularly limited.

For example, there are enumerated glycidylethers (B₁) of a polyvalentalcohol and glycidylesters (B₂) of a polybasic acid.

As an example of the glycidylethers (B₁) of a polyvalent alcohol, thereare enumerated glycerine triglycidylether, trimethylolpropanetriglycidylether, pentaerythyritol tetraglycidylether, and sorbitolhexaglycidylether, etc.

Further, as an example of the glycidylesters (B₂) of a polybasic acid,there is enumerated a glycidylester of hexahydrophthalic acid.

Polyepoxide (B′) which is preferably employed in the present inventionis an acrylic polyepoxide (B′) which is obtained by copolymerization of10-60% by weight, and preferably 15-50% by weight of an ethylenicunsaturated monomer (e) containing an epoxy group with 40-90% by weight,and preferably 50-80% by weight of an ethylenic unsaturated monomer (h)not containing an epoxy group.

In the case that the ethylenic unsaturated monomer (e) containing anepoxy group is not more than 10% by weight, curability is short and, inthe case of more than 60% by weight, a resin becomes too hard andweatherability becomes short.

As the ethylenic unsaturated monomer (e) containing an epoxy group, forexample, there are enumerated glycidyl(meth)acrylate,β-methylglycidyl(meth)acrylate, and 3,4-epoxycyclohexenyl(meth)acrylate, etc. In order to prepare a coating composition which iswell-balanced between curability and storage stability,glycidyl(meth)acrylate is preferably employed.

As the ethylenic unsaturated monomer (h) not containing an epoxy group,there are enumerated monomers described hereinabove as the ethylenicunsaturated monomer (d₁) not containing an acid anhydride group in orderto prepare the polymer (A3) containing acid anhydride groups.Copolymerization can be also likewise conducted as describedhereinabove.

In the acrylic polyepoxide (B′) obtained, a number average molecularweight is 200-10000, preferably 500-8000, and more preferably 800-5000.In the case that the number average molecular weight is less than 200,curability lowers in a coating layer obtained and, in the case ofexceeding 10000, solid component lowers in a coating. Further, an epoxyequivalent is 50-700, preferably 80-600, and more preferably 100-500. Inthe case that the epoxy equivalent is more than the maximum value,curability becomes unpreferably insufficient in a coating composition.

Further, in the case that it is less than the minimum value, a coatinglayer becomes unpreferably too hard and brittle.

Further, in order to prepare the ethylenic unsaturated monomer (d₁) notcontaining an acid anhydride group, the ethylenic unsaturated monomer(d₃) containing hydroxyl group can be employed as the ethylenicunsaturated monomer (h) not containing an epoxy group.

Particularly, in the case that the ethylenic unsaturated monomer (d₃)containing hydroxyl group is employed as the ethylenic unsaturatedmonomer (h) not containing an epoxy group, adhesion and a recoatingproperty, etc. are elevated in a coating layer obtained. Still further,since an acrylic polyepoxide having hydroxy group and epoxy groupobtained by employing the ethylenic unsaturated monomer (d₃) containinghydroxyl group as the ethylenic unsaturated monomer (h) not containingan epoxy group, as described hereinafter, reacts and connects with anacrylic polycarboxylic acid (A′) having carboxylic groups andcarboxylate groups at both functional groups which are hydroxyl groupsand carboxylic groups, a stronger coating layer can be obtained.

In the acrylic polyepoxide (B′) obtained, a hydroxyl value is 5-300mgKOH/g solid, preferably 10-200 mgKOH/g solid, and more preferably15-150 mgKOH/g solid. In the case that the hydroxyl value exceeds 300mgKOH/g solid, solid components lower in a coating and water resistanceis insufficient in a cured coating layer and, in the case of less than 5mgKOH/g solid, adhesion is poor.

A particularly preferred polyepoxide (B″) to be employed in the presentinvention is obtained by copolymerization of (i) 5-70% by weight of theethylenic unsaturated monomer (d₃) containing hydroxyl group which hasthe organic chain shown by the general formula (4) or the organic chainshown by the general formula (6), (ii) 10-60% by weight of the ethylenicunsaturated monomer (e) containing an epoxy group, and optionally, (iii)0-85% by weight of the ethylenic unsaturated monomer (d₄) notsimultaneously containing hydroxyl group and epoxy group.

In the case, the polyepoxide (B″) having hydroxyl group and an epoxygroup has preferably 2-12 pieces, more preferably 3-10 pieces of epoxygroups on an average and preferably 0.5-10 pieces, more preferably 1-8pieces of hydroxyl group.

The polyepoxide (B″) component can be formulated in an amount of 10-80%by weight, preferably 20-70% by weight, and more preferably 30-65% byweight based on total solid of the curable resin composition. In thecase that the amount of the polyepoxide (B″) is less than 10% by weight,curability lowers in a coating layer obtained and, in the case ofexceeding 80% by weight, yellowing resistance becomes worse.

I-5. <Anti Oxidant (I-C)>

Usually, a hydrocarbon-based polymer suffers an oxidizing deteriorationsuch as heat, light, oxygen, and mechanical shear force duringpreparation, processing, and using. It is known that the oxidizingdeterioration depends upon an action of a self-oxidizing mechanism whichis a radical continuous chain reaction.

An antioxidant for preventing the oxidizing deterioration of a polymeris classified into a radical continuous chain inhibitor (a primaryantioxidant) such as a phenol-based antioxidant and an amine-basedantioxidant, and a peroxide decomposing agent (a secondary antioxidant)such as a phosphorus-based antioxidant and a sulphur-based antioxidant.

The anti oxidant (IX-C) to be employed in the curable resin compositionof the present invention is a phenol-based antioxidant (C₁), aphosphite-based antioxidant (C₂), and a thioether-based antioxidant(C₃). Any one of those may be even employed solely, and two or morekinds thereof are effectively employed in combination for ananti-yellowing property because of different anti-oxidizing mechanismsin the respective antioxidants.

The phenol-based antioxidant (C₁) is preferably employed in combinationwith the phosphite-based antioxidant (C₂) or the thioether-basedantioxidant (C₃). By employing the phenol-based antioxidant (C₁) incombination with the phosphite-based antioxidant (C₂), an anti-yellowingproperty is particularly preferably improved.

The phenol-based antioxidant (C₁) preferably has a highly massive andbulky substituent group such as, for example, t-butyl group at an orthoposition of a phenol. Because, there is not apt to be caused a chaintransferring of a free radical caught, and stability increases. Morepreferably, there is enumerated one having a bulky substituent group atboth ortho positions.

As the phenol-based antioxidant (C₁), there are enumerated2,6-di-t-butylphenol, 2,4-di-t-butylphenol,2-t-butyl-4,6-di-methyl-phenol, 2,6-di-t-butyl-4-methylphenol,2,6-di-t-butyl-4-ethylphenol, 2,4,6-tri-t-butylphenol,2,6-t-butyl-4-hydroxymethylphenol,2,6-di-t-butyl-2-dimethylamino-p-cresol,n-octadecyl-3-(3′,5′-di-t-butyl-4-hydroxyphenyl)propionate,styrenatephenol, 2,2′-methylene-bis-(4-methyl-6-t-butylphenol),2,2′-methylene-bis-(6-cyclohexyl-4-methylphenol),2,2′-butylidene-bis-(2-t-butyl-4-methylphenol),4,4′-methylene-bis-(2,6-di-t-butylphenol),1,6-hexanediol-bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate,tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane,1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane, and3,9-bis[1,1-di-methyl-2-{-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspyro[5,5]undecane,etc.

Preferred phenol-based antioxidant (C₁) are 2,6-di-t-butylphenol,2-t-butyl-4,6-di-methyl-phenol, 2,6-di-t-butyl-4-methylphenol,2,6-di-t-butyl-4-ethylphenol, 2,4,6-tri-t-butylphenol, styrenatephenol,2,2′-methylene-bis-(4-methyl-6-t-butylphenol),2,2′-methylene-bis-(6-cyclohexyl-4-methylphenol),4,4′-methylene-bis-(2,6-di-t-butylphenol), andtetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane,etc.

As commercially supplied phenol-based antioxidant (C₁), for example,there are enumerated Sumilizer (Sumilizer)BHT, Sumilizer-S,Sumilizer-BP-76, Sumilizer-MD-PS, Sumilizer-BP-101, Sumilizer-GA-80,Sumilizer-BBM-S, Sumilizer-WX-R, Sumilizer-MW, Sumilizer-GM, andSumilizer-GS which are manufactured by Sumitomo Kagaku, Ltd., andAdekastab A0-20, Adekastab A0-30, Adekastab A0-40, Adekastab A0-50,Adekastab A0-60, Adekastab A0-75, Adekastab A0-80, Adekastab A0-330,Adekastab A0-616, Adekastab A0-635, Adekastab A0-658, Adekastab A0-15,Adekastab A0-18, Adekastab 328, and Adekastab 37, etc. which aremanufactured by Asahi Denka, Ltd.

As the phosphite-based antioxidant (C₂), for example,tris(isodecyl)phosphite, tris(tridecyl)phosphite, phenyldiisodecylphosphite, diphenylisooctyl phosphite, triphenyl phosphite,tris(nonylphenyl)phosphite, 4,4′-isopropylidene-diphenolalkyl phosphite,tris(mono- and di-mixed nonylphenyl)phosphite,tris(2,4-di-t-butylphenyl)phosphite, distearylpentaerythritoldiphosphite, di(2,4-di-t-butylphenyl)pentaerythritol diphosphite,di(nonylphenyl)pentaerythritol diphosphite, phenyl-bisphenol Apentaerythritol diphosphite,tetratridecyl-4,4′-butylidenebis-(3-methyl-6-t-butylphenol)-di-phosphite,and hexatridecyl1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butanetriphosphite, etc.

Preferred phosphite-based antioxidant (C₂) are tris(isodecyl)phosphite,phenyldiisodecyl phosphite, diphenylisooctyl phosphite, triphenylphosphite, distearylpentaerythritol diphosphite,di(nonylphenyl)pentaerythritol diphosphite, phenyl-bisphenol Apentaerythritol diphosphite, andtetratridecyl-4,4′-butylidenebis-(3-methyl-6-t-butylphenol)-di-phosphite,etc.

As commercially supplied phosphite-based antioxidant (C₂), for example,there are enumerated Sumilizer TMP, and Sumilizer TPP-R, Sumilizer P-16which are manufactured by Sumitomo Kagaku, Ltd., and Adekastab PEP-2,Adekastab PEP-4C, Adekastab PEP-8, Adekastab PEP-8F, Adekastab PEP-8W,Adekastab PEP-11C, Adekastab PEP-24G, Adekastab PEP-36, Adekastab HP-10,Adekastab 2112, Adekastab 260, Adekastab P, Adekastab QL, Adekastab522A, and Adekastab 329K, Adekastab 1178, Adekastab 1500, Adekastab C,Adekastab 135A, Adekastab 517, Adekastab 3010, and Adekastab TPP, etc.which are manufactured by Asahi Denka, Ltd.

As the thioether-based antioxidant (C₃), for example, there areenumerated dilauryl-3,3′-thiodipropionate,ditridecyl-3,3′-thiodipropionate, dimylistyl-3,3′-thiodipropionate,distearyl-3,3′-thiodipropionate,bis(2-methyl-4-{3-n-alkylthiopropionyloxy}-5-t-butylphenyl) sulphide,pentaerythritol-tetrakis-(β-lauryl-thiopropionate), and2-mercaptobenzimidazole, etc.

As commercially supplied thioether-based antioxidant (C₃), for example,there are enumerated Sumilizer TPL-R, Sumilizer TPM, Sumilizer TPS,Sumilizer TP-D, Sumilizer TL, and Sumilizer MB which are manufactured bySumitomo Kagaku, Ltd., and Adekastab A0-23, Adekastab A0-412S, andAdekastab A0-503A, etc. which are manufactured by Asahi Denka, Ltd.

The antioxidant (IX-C) is formulated in a proportion of 0.1-10% byweight, preferably 0.5-8% by weight, and more preferably 1-7% by weightbased on total solid components in the curable resin composition[A′+(IX-B)+(IX-C)]. In the case that the amount of the antioxidant isless than 0.1% by weight, yellowing is remarkably observed in bakingand, in the case of exceeding 10% by weight, curability lowers in acoating layer.

II. <Curable Resin Composition>

II-1. <Formulation of the Curable Resin Composition>

The curable resin composition of the present invention is obtained byformulating the acrylic polycarboxylic acid resin (A′) and thepolyepoxide (IX-B), or the acrylic polycarboxylic acid resin (A′), thepolyepoxide (IX-B), and the antioxidant (IX-C).

Formulation of the acrylic polycarboxylic acid resin (A′), thepolyepoxide (IX-B), and the antioxidant (IX-C) can be readily conductedin an amount and method well known by a skilled person in the art.Particularly, in the case of using an acrylic polycarboxylic acid resin(A*′) having carboxylic groups and carboxylate groups, and a polyepoxide(B′) having hydroxyl group and an epoxy group as a polyepoxide, therecan be obtained a curable resin composition having a high solid contentwhich can provide a coating layer having an excellent acid resistance.

In the case, the formulation is conducted in a molar ratio of thecarboxylic groups contained in the acrylic polycarboxylic acid resin(A*′) with respect to the epoxy group contained in the polyepoxide (B′)of 1/1.2-1/0.6, and preferably 1/1.0-1/0.8, and molar ratio of thecarboxylate groups contained in the acrylic polycarboxylic acid resin(A*′) with respect to the hydroxyl group contained in the polyepoxide(B′) of 1/1.5-1/0.2, preferably 1/1.2-1/0.25, and more preferably1/1-1/0.3.

In the case that the molar ratio of the carboxylic groups contained inthe resin (A*′) with respect to the epoxy group contained in thepolyepoxide (B′) is less than 1/1.2, a coating layer yellows and, in thecase of exceeding 1/0.6, curability lowers in a resin compositionobtained. In the case that the molar ratio of the carboxylate groupscontained in the resin (A*′) with respect to the hydroxyl groupcontained in the polyepoxide (B′) is less than 1/1.5, water resistancelowers because of excessive hydroxyl groups and, in the case ofexceeding 1/0.2, curability lowers in a resin composition obtained. Theformulating amount can be calculated from a hydroxyl value, acid value,and epoxy equivalent of resins according to a calculating method wellknown by a skilled person in the art.

In thus-obtained curable resin composition of the present invention, acuring mechanism is as follows. First of all, the carboxylic group reactwith the carboxylate groups in the acrylic polycarboxylic resin (A′) orthe resin (A*′) by heating to form acid anhydride groups in a polymer,and a free monoalcohol is produced. The monoalcohol produced is removedout of a system by evaporation. The acid anhydride groups produced in apolymer form again carboxylic groups by forming crosslinking pointsthrough a reaction with the hydroxyl groups contained in the polyepoxide(IX-B). The carboxylic groups form crosslinking points by a reactionwith the epoxy groups in the polyepoxide (IX-B). As describedhereinabove, a high crosslinking density can be provided by an advanceof a curing.

II-2. <Polyester Polycarboxylic Acid>

In addition to the above-described essential components, there can beoptionally formulated a binder component such as a polyesterpolycarboxylic acid (IX-D) into the curable resin composition of thepresent invention. It is effective for elevating a solid content in acoating layer obtained.

The polyester polycarboxylic acid (IX-D) to be employed in the curableresin composition of the present invention is obtained by ahalf-esterification reaction of a polyester polyol (k) having at leastthree hydroxyl groups with an acid anhydride.

In the present invention, the polyester polyol (k) means a polyvalentalcohol having at least one ester bond chain, and preferably at leasttwo ester bond chains.

The polyester polycarboxylic acid (IX-D) to be employed in the curableresin composition of the present invention has an acid value of 50-350mgKOH/g solid, preferably 100-300 mgKOH/g solid, and more preferably150-250 mgKOH/g solid, a number average molecular weight of 400-3500,preferably 500-2500, and more preferably 700-2000, and weight averagemolecular weight/number average molecular weight of not more than 1.8,preferably not more than 1.5, and more preferably not more than 1.35.

In the case that the acid value exceeds 350 mgKOH/g solid, polymerviscosity becomes too high, resulting in that concentration of solidcomponents lowers and, in the case that the acid value is less than 50mgKOH/g solid, curability is short in a coating layer.

In the case that the molecular weight exceeds 3,500, polymer viscositybecomes too high, resulting in that handling becomes difficult andconcentration of solid components lowers in a coating composition and,in the case that the molecular weight is less than 400, curability isshort in a coating layer or water resistance lowers in a coating layer.In the case that the weight average molecular weight/number averagemolecular weight exceeds 1.8, water resistance lowers or weatherabilitylowers in a coating layer.

Further, the polyester polycarboxylic acid (IX-D) may even have ahydroxyl value of not more than 150 mgKOH/g solid, preferably 5-100mgKOH/g solid, and more preferably 10-80 mgKOH/g solid, whereby,adhesion elevates in a coating layer obtained. In the case that thehydroxyl value exceeds 150 mgKOH/g solid, water resistance lowers in acoating layer.

Half-esterification can be conducted by same operations using theabove-described acid anhydride for preparing the ethylenic unsaturatedmonomer having carboxylic group to be employed as the ethylenicunsaturated monomer (d₁) not having an acid anhydride group. However,the hydroxyl groups may be even remained without necessity of changingall the hydroxyl groups in the polyester polyol (k) to carboxylicgroups. The polyester polycarboxylic acid (D₁) having hydroxyl groupsprovides a coating layer having an excellent adhesion such as arecoating property compared to the polyester polycarboxylic acid (D₂)not having hydroxyl group.

Further, since the polyester polycarboxylic acid (D₃) having hydroxylgroups and carboxylic groups, as described hereinafter, can react andconnect to both of the polyepoxide (B′) and the acrylic polycarboxylicacid resin (A′), there can be obtained a tough coating layer.

There is preferred one having not less than 0.1 piece of hydroxyl groupson an average in the molecule.

In general, mol amount of acid anhydride groups with respect to molamount of OH groups in the polyester polyol (k) is desirably controlledin 0.2-1.0 times and, particularly 0.5-0.9 times. In the case that themol amount of acid anhydride groups with respect to mol amount of OHgroups is less than 0.2, curability is short in a coating layer.

The polyester polyol (k) to be employed herein provides a polyesterpolycarboxylic acid (D) having at least two acid-functional groups inthe molecule and the above-described characteristics by reacting with anacid anhydride.

In general, such the polyester polyol (k) is prepared by condensation ofa low molecular weight polyvalent alcohol having at least three hydroxylgroups and a carbon number of 3-16 with a linear aliphatic dicarboxylicacid. By introducing a linear aliphatic group into the low molecularweight polyvalent alcohol, flexibility is given in a coating layerobtained, whereby, impact resistance elevates.

As the low molecular weight polyvalent alcohol to be employed, there areenumerated trimethylol propane, trimethylol ethane, 1,2,4-butanetriol,ditrimethylol propane, pentaerythritol, dipentaerythritol, glycerine,and a mixture thereof.

As the dicarboxylic acid, there are enumerated a dibasic acid such asphthalic acid, isophthalic acid, terephthalic acid, succinic acid,adipic acid, azelaic acid, sebasic acid, tetrahydrophthalic acid,hexahydrophthalic acid, maleic acid, fumaric acid, and a mixturethereof. Further, there can be employed an acid anhydride such assuccinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride,hexahydrophthalic anhydride, hymic anhydride, trimellitic anhydride,methylcyclohexene tricarboxylic anhydride, pyromellitic anhydride, and amixture thereof.

The polyester polyol (k) is synthesized by a usual esterificationreaction. That is, it is polyesterized by a dehydrating condensationreaction of a polyvalent alcohol with a polybasic acid, anesterification of a polyvalent alcohol with an acid anhydride and then adehydrating reaction with an alkyl component. By such the operations, anoligomer of a polyester polyol (k) having a relatively low molecularweight, and there is provided a coating composition having a high solid.

A particularly preferred polyester polyol (k) to be employed in thepresent invention is obtained by chain extending through addition of alactone compound such as ε-caprolactone to a low molecular weightpolyvalent alcohol. Since a molecular weight distribution becomes sharp,a coating composition becomes high-solid, and there is obtained acoating layer having an excellent weatherability and water resistance.

As a low molecular weight polyvalent alcohol to be particularlypreferably employed in the case, there are enumerated trimethylolpropane, ditrimethylol propane, and pentaerythritol, etc.

The lactone compound to be employed in the present invention may be acyclic compound which produces hydroxyl group at a terminal byring-opening through reacting with a nucleophilic agent because of thepresence of oxygen atom in the ring. A preferred lactone compound has acarbon number of 4-7. Because, it readily causes a ring-opening additionreaction.

As a specific example of the lactone to be preferably employed, alreadyexemplified ones are enumerated, and there are preferably employedε-caprolactone, δ-varelolactone, and γ-butyrolactone.

Chain extension can be conducted by the same conditions as in a usualring opening addition reaction. For example, a polyester polyol (k) isobtained by allowing to react at 80-200° C. within 5 hours in anappropriate solvent or the absence of a solvent, which is chain-extendedby a low molecular weight polyvalent alcohol. A tin-based catalyst maybe even employed.

In the case, a mol amount of the lactone compound is 0.2-10 times,preferably 0.25-5 times, and more preferably 0.3-3 times with respect toa mol amount of OH group in the low molecular weight polyvalent alcohol.In the case that the mol amount of the lactone compound with respect toa mol amount of OH group is less than 0.2 times, a resin becomes hard,and impact resistance lowers in a coating layer and, in the case ofexceeding 10 times, hardness lowers in the coating layer.

The polyester polycarboxylic acid (IX-D) component can be formulatedwithin 70% by weight, preferably 5-50% by weight, and more preferably10-40% by weight based on total solid in the curable resin composition.In the case that amount of the polyester polycarboxylic acid (IX-D) isless than 5% by weight, solid concentration does not increase in acoating and, in the case of exceeding 70% by weight, weatherabilitylowers in a coating layer obtained.

II-3. <Silicone Polymer (IX-L)>

In the curable resin composition of the present invention, there can beoptionally formulated a binder component such as a silicone polymer(IX-L). It is effective for elevating a solid component concentration ina coating layer obtained.

The silicone polymer (IX-L) to be employed in the present invention is,for example, a silicone polymer having an epoxy group and/or an alkoxygroup.

As the silicone polymer (L₁) having epoxy groups, for example, there isenumerated a “NUC silicone” series manufactured by Nihon Unicar, Ltd.

As the silicone polymer (L₂) having alkoxy groups, for example, there isenumerated “KC89-S”, etc. manufactured by Shin-etsu Kagaku Kogyo, Ltd.

As the silicone polymer (L₃) having epoxy groups and alkoxy groups, forexample, there are enumerated “MKC silicate MSEP 2” series manufacturedby Mitsubishi Kagaku, Ltd., and a “NUC silicone” series manufactured byNihon Unicar, Ltd.

A method for the preparation of such the silicone polymers is describedin pages 29-30 of Abstracts in Organic Silicone Material ChemicalSymposium in 1990. The epoxy group can exist at middle portions orterminals of a linear or cyclic hydrocarbon chain.

In the present invention, an epoxy equivalent represents g-number of acompound containing 1 g equivalent of an epoxy group, an alkoxyequivalent represents g-number of a compound containing 1 g equivalentof an alkoxy group, and a hydroxyl group equivalent represents g-numberof a compound containing 1 g equivalent of hydroxyl group.

In the silicone polymer (IX-L), the epoxy equivalent is 100-1500, andthe alkoxy equivalent is 50-1500. In the case that the epoxy equivalentis less than 100, storage stability becomes poor in a coating and, inthe case of exceeding 1500, curability becomes poor. A range of theepoxy equivalent is preferably 140-1000, and more preferably 180-700. Arange of the alkoxy equivalent is preferably 60-800, and more preferably80-500.

Such the silicone polymer (L₃) component having epoxy groups and alkoxygroups can be formulated within 30% by weight based on the total solidweight of the curable resin composition, preferably 3-20% by weight, andmore preferably 5-15% by weight.

In the case that an amount of the silicone polymer (L₃) componentexceeds 30% by weight, storage stability becomes poor in a coatingobtained.

In the present invention, a silicone polymer (L₄) having hydroxyl groupsand carboxylic groups can be employed together with or in place of thesilicone polymers (L₁, L₂, and L₃) having epoxy groups and/or alkoxygroups. The silicone polymer (L₄) having hydroxyl groups and carboxylicgroups is obtained by a half-esterification reaction of a siliconepolymer having hydroxyl group with a compound having an acid anhydridegroup.

In the silicone polymer (L₄), a number average molecular weight is500-6000, and preferably 1000-4500, a hydroxyl group value is 2-120mgKOH/g solid, and preferably 10-80 mgKOH/g solid, and an acid value is20-180 mgKOH/g solid, and preferably 35-150 mgKOH/g solid. In the casethat the number average molecular weight and hydroxyl group value oracid value exceed maximum value of the ranges, it becomes difficult toprepare a coating having a sufficiently high solid content and, in thecase of less than minimum value of the ranges, curability lowers in acoating.

The silicone polymer having hydroxyl groups is commercially supplied,for example, there are enumerated KR-2001 manufactured by Shin-etsuSilicone, Ltd., and NUC silicone series manufactured by Nihon Unicar,Ltd., etc.

The silicone polymer having hydroxyl groups has preferably 3-12 piecesof hydroxyl groups on an average in the molecule. In the case that thehydroxyl groups is less than 3 on an average, curability is short and,in the case of exceeding 12, viscosity becomes high, resulting in thatit becomes difficult to increase solid content in the case ofpreparation of a coating composition.

The compound having an acid anhydride group, if it is a compound whichcan provide a carboxyl-functional property by reacting with hydroxylgroup in usual reaction conditions such as a room temperature to 120° C.and an ordinary pressure, is not particularly limited. By the use of acompound having an acid anhydride group and having a saturated orunsaturated cyclic group of a carbon number of 8-12, compatibility witha resin becomes preferably excellent.

As the compound having an acid anhydride group, for example, there areenumerated hexahydrophthalic anhydride, phthalic anhydride,4-methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, andtrimellitic anhydride, etc.

Half-esterification reaction of the silicone polymer having hydroxylgroup with the compound having an acid anhydride group is conductedaccording to usual methods, for example, at room temperature to 120° C.for 30 minutes to 8 hours. In the case that the reaction is conductedfor a long time of period exceeding 120° C., polyesterization reactionis caused and there is produced a silicone polyester (IX-L) having ahigh molecular weight. Since such the silicone polyester (IX-L) has asmall amount of functional groups and high viscosity, it is notpreferred to be employed in the present invention.

Such the silicone polymer (L₄) having hydroxyl groups and carboxylicgroups can be formulated within 30% by weight based on the total solidweight of the curable resin composition, preferably 3-20% by weight, andmore preferably 5-15% by weight. In the case that an amount of thesilicone polymer (L₄) component exceeds 30% by weight, storage stabilitybecomes poor in a coating obtained.

In the case that the silicone polymer (L3) having epoxy groups andalkoxy groups is employed together with the silicone polymer (L₄) havinghydroxyl groups and carboxylic groups, total amount is within 30% byweight based on the total solid weight of the curable resin composition,preferably 3-20% by weight, and more preferably 5-15% by weight. In thecase that an amount of the silicone polymers (L₃+L₄) component exceeds30% by weight, storage stability becomes poor in a coating obtained.

II-4. <Catalyst for Curing>

In addition to the above-described components, a catalyst for curing(IX-F) is employed in the curable resin composition of the presentinvention. For example, there may even contain a catalyst for curing(F₁) such as a quaternary ammonium salt to be usually employed for anesterification reaction of an acid with an epoxide. As specific examplesof other catalyst for curing (F₂) to be employed in the curable resincomposition of the present invention, there are enumeratedbenzyltriethyl ammonium chloride or bromide, tetrabutyl ammoniumchloride or bromide, salysilate or glycolate, paratoluene sulphonate,nitrate, dibutyl phosphate, di-2-ethylhexyl phosphate, trimethylbenzylammonium dibutylphosphate, trimethylcetyl ammonium butylphosphate, octyltrimethyl ammonium dimethylphosphate, and dodecyltrimethyl ammoniumdiphenylphosphate, etc. These catalysts for curing may be even employedin mixing.

The catalyst for curing (IX-F) can be usually employed in 0.01-3.0% byweight based on the total solid weight of resin composition, preferably0.1-1.5% by weight, and more preferably 0.4-1.2% by weight. In the casethat an amount of the catalyst for curing (IX-F) is less than 0.01% byweight, curability lowers and, in the case of exceeding 3.0% by weight,storage stability lowers.

II-5. <Tin-Based Catalyst (IX-G)>

Further, as described in JP-A-02151651 and JP-A-02279713 OfficialGazettes, a tin-based compound may be even employed together therewith.As the tin-based catalyst (IX-G), for example, there are enumerateddimethyltin bis(methylmaleate), dimethyltin bis(ethylmaleate),dimethyltin bis(butylmaleate), and dibutyltin bis(butylmaleate), etc.

The tin-based compound (IX-G) can be usually employed in 0.2-6% byweight based on the total solid weight of resin composition, preferably0.3-4.0% by weight, and more preferably 0.4-3.0% by weight.

In the case that an amount of the tin-based compound (IX-G) to beemployed is less than 0.2% by weight, storage stability lowers and, inthe case of exceeding 6% by weight, weatherability lowers.

In the case that the catalyst (IX-F) for curing is employed togetherwith the tin-based catalyst (IX-G), weight ratio of the catalyst (IX-F)for curing with respect to the tin-based catalyst (IX-G) is preferablyadjusted to 1/4-1/0.2.

II-6. <Other Additives (H)>

In order to elevate water resistance by elevating crosslinking, ablocked isocyanate may be even added in the curable resin composition ofthe present invention. Further, in order to improve weatherability in acoating layer, there may be even added an ultraviolet ray absorbent anda hindered amine photostabilizer, and an antioxidant, etc.

Still further, as a rheology controlling agent, a crosslinked resinparticles (IX-E) may be added and, in order to control an outerappearance, a surface controlling agent may be even added.

In the case that the crosslinked resin particles (IX-E) are employed,those are added in an amount of 0.01-10 parts by weight, preferably0.1-5 parts by weight with respect to 100 parts by weight of solid resinof the curable resin composition of the present invention. In the casethat the amount of the crosslinked resin particles (IX-E) exceed 10parts by weight, outer appearance becomes worse and, it is less than0.01 part by weight, a rheology controlling effect is not obtained.

Further, as a dilution agent in order to control a viscosity, there maybe even added an alcohol-based solvent (for example, methanol, ethanol,propanol, and butanol, etc.), a hydrocarbon-based and ester-basedsolvent, etc.

Still further, the resin to be employed in the present invention has anacid group as a functional group. Accordingly, by neutralization usingan amine, it can be also changed to a water-based composition containingwater as a medium.

III. <Coating Composition and Preparation of a Coating Layer>

Method for the preparation of the coating composition of the presentinvention is not particularly limited and, there can be applied allmethods which are well known in skilled person in the art.

The coating composition of the present invention can be coated by spraycoating, brush coating, immersion coating, roll coating, and flowcoating, etc. A substrate may be even optionally under-coated ormiddle-coated. As an under coating and a middle coating, publicly-knownones can be employed.

The coating composition of the present invention can be advantageouslyemployed for, for example, woods, metals, glass, cloth, plastics, andfoams, etc., particularly, surface of the plastics and metals, forexample, steels, aluminum, and an alloy thereof. In general, layerthickness changes depending upon desired uses. In many cases, it isuseful in 0.5-3 mil.

After coating onto the substrate, coating layer is cured.

A cured coating layer having a high crosslinking degree is obtained at acuring temperature of 100-180° C., preferably 120-160° C. Curing time ofperiod changes depending upon the curing temperature, etc., and it isappropriate in 120° C.-160° C. for 10-30 minutes.

By the curable resin composition in relation to the present invention, ahigh solid coating can be prepared, and a coating layer derived from thecoating is excellent in acid resistance against an acid rain, abrasionresistance, yellowing resistance, and outer appearance, and it is anexceedingly useful composition.

Hereinafter, the present invention X is illustrated in detail.

As a polymerizable unsaturated monomer having carboxylic group to beemployed in the present invention, for example, there are enumerated atleast one selected from the group consisting of (meth)acrylic acid,itaconic acid, β-(meth)acryloyloxy ethylsuccinate, β-(meth)acryloyloxyethylmaleate, β-(meth)acryloyloxy ethylphthalate, maleic acid, amonoalkylmaleate (a carbon number of 1-12 in the alkyl group),tetrahydrophthalic acid, and an anhydride thereof. Of those, acrylicacid and methacrylic acid are particularly preferred.

The present invention is comprised a composition obtained by allowing toreact in a reaction molar ratio of a radical polymerizable unsaturatedmonomer having carboxylic group of more than 1 in the case of preparinga lactone-modified radically polymerizable unsaturated monomer havingcarboxylic group by ring-opening polymerization of a lactone with theradically polymerizable unsaturated monomer having carboxylic group. Inmore detail, it is comprised a composition obtained by allowing to reactthe lactone with the polymerizable unsaturated monomer having carboxylicgroup at a temperature of approximately 80° C. to approximately 140° C.in an atmosphere containing oxygen under the presence of a catalyst lessthan 1000 ppm and an inhibitor less than 1000 ppm in order to prevent apolymerization of the polymerizable unsaturated monomer havingcarboxylic group.

Use amount of ε-caprolactone with respect to the radically polymerizableunsaturated monomer having carboxylic group is decided depending upon amolecular weight of a desired product, and it is particularly affectedby an amount of the catalyst, a kind of a solvent, and an amount of thesolvent. In order to reduce a lactone continuous chain, it is allowed toreact with respect to not less than 0.3 mol and not more than 1 mol,preferably 0.35-1 mol, and more preferably 0.5-0.75 mol with respect to1 mol of the radically polymerizable unsaturated monomer havingcarboxylic group. In the case that the reaction amount of the lactone ismore than 1 mol, the lactone continuous chain becomes large and, in thecase that it is employed, for example, as a raw material for a coating,although curing reactivity and flexibility become good, hardness andacid resistance lower in a cured article. Further, in the case of lessthan 0.35, abrasion resistance becomes worse.

As a catalyst to be employed in Nos. 15-16 of the present invention X,for example, there are enumerated a Lewis acid such as aluminum chlorideand stannous chloride, a Br nsted acid such as sulfuric acid, p-toluenesulphonate, benzene sulphonate, and a sulfonic acid-type ion-exchangeresin, and there are preferred sulfuric acid, p-toluene sulphonate, andbenzene sulphonate, since these are soluble in reaction liquid.

Use amount of the catalyst is preferably 0.1-50 parts by weight, andmore preferably 0.1-20 parts by weight with respect to 100 parts byweight of the polymerizable unsaturated monomer having carboxylic group.In the case of employing the sulfonic acid-type ion-exchange resin, alarge amount is required compared to sulfuric acid and p-toluenesulphonate.

As a catalyst to be employed in Nos. 15-16 of the present invention,although there have been conventionally employed aluminum chloride,stannous chloride, sulfuric acid, p-toluene sulphonate, benzenesulphonate, and the sulfonic acid-type ion-exchange resin, etc., eventhough intending to allow to add ε-caprolactone at a high temperature,since (meth)acrylic acid itself thermally-polymerizes, it is difficultto obtain a desired product, or there is observed discoloration of aproduct. At a low temperature, event though being capable of preventinga polymerization of acrylic acid itself, a ring-opening reaction rate ofε-caprolactone is very slow.

In the present invention, there is desirably employed a catalyst havinga strong catalytic activity by which a reaction sufficiently proceeds ata low temperature such as 80-130° C. and a small amount of the catalyst,and discoloration is low in a product obtained. From such a viewpoint,there are employed stannic chloride, monobutyltin tris-2-eyhylhexanoate,stannic octoate, and dibutyltin dilaurate, etc. Of those, discolorationcan be decreased by the use of monobutyltin tris-2-eyhylhexanoate, andconcentration of a catalyst can be increased, and it is very excellentin a viewpoint of shortening of a reaction time of period.

Addition amount of the catalyst is 1-1000 ppm, and preferably 10-500ppm.

By the use of the catalyst, there can become prepared a polyesterunsaturated monomer composition modified by a small amount of lactonesin which lactone continuous chains are decreased, and which is usefulfor preparing a polyester unsaturated monomer composition modified by asmall amount of lactone. In contrast of a decrease of the lactonecontinuous chains, although there are remained unreacted polymerizableunsaturated monomers having carboxylic groups, since the unreactedpolymerizable unsaturated monomers having carboxylic groups are oftenemployed solely, if it is within 50 wt %, even mixed monomers can beoften employed.

However, in the case that 1 mol of the lactone is added to 1 mol of thepolymerizable unsaturated monomers having carboxylic groups, a reactionproduct is the compound represented by the above-described formula (1).

In a reaction composition, there are statistically distributed anunreacted substance having n=0 and polylactones having n=1, 2, 3, 4, 5 .. . . Herein, n is preferably not more than 2 and, an average value of nin the composition is not less than 0.3 and less than 1.0.

However, since it is difficult to industrially separate and refinethose, in order to decrease products having not less than 2 continuouschains, a feeding amount for reaction of the lactone such asε-caprolactone is decreased to not more than 1 mol with respect to 1 molof the polymerizable unsaturated monomers having carboxylic groups.

As the lactone monomers, there is preferred a lactone having 5, 6, 7,and 8-membered ring, for example, ε-caprolactone and/or varelolactone,etc. are enumerated. Further, in the case that ε-caprolactone isemployed as the lactones, other cyclic lactones such astrimethylcaprolactone and varelolactone can be also partially employedin addition to ε-caprolactone.

The polyester unsaturated monomer composition modified by a small amountof lactones in relation to the present invention Nos. 15-16 is obtainedby separating and removing unreacted (meth)acrylic acid from a reactionmass. As a method for separating and removing the unreacted(meth)acrylic acid, there are enumerated distilling separation,neutralizing separation (further, water washing may be also conducted)by a basic substance, and ion-exchanging separation, etc.

As solvents to be employed in the present invention, there areenumerated solvents which do not react with the catalysts, the lactones,and the polymerizable unsaturated monomers having carboxylic groups, andwhich include aromatic hydrocarbons such as benzene, toluene, andxylene. Further, it can be also prepared even in the absence of thesolvents.

There is specifically illustrated below a method for the preparation ofthe polyester unsaturated monomer composition modified by a small amountof lactones of the present invention, in which the reaction is conductedby collectively or continuously adding the lactones under the presenceof 0.01-1% by weight, preferably 0.03-0.5% by weight of the catalystsand, optionally, a polymerization inhibitor such as hydroquinone,hydroquinone monomethylether, BHT, and phenothiazine at a reactiontemperature of 40-150° C., and preferably 60-150° C. based on 100 partsof the radically polymerizable unsaturated monomer having carboxylicgroup.

The solvents can be employed in concentration of, for example, 0-95% byweight (amount of solvents) in a reaction liquid.

In the polyester unsaturated monomer composition modified by a smallamount of lactones prepared by the above-described method for thepreparation of the present invention, residual amount of the lactones is0-10% by weight (hereinafter, GPC area %), content of the polyesterunsaturated monomer modified by a small amount of lactones is not lessthan 20% by weight and not more than 50% by weight, content of adi(meth)acrylate which is a by-product is not more than 2% by weight,content of other by-products prepared by Michaels addition, acrylicpolymerization, esterification or other side reactions is not more than10% by weight, content of the catalysts is less than 1000 ppm, andcontent of the polymerization inhibitors is not more than 1%.

The polyester unsaturated monomer composition modified by a small amountof lactones of the present invention can provide an acrylic polyol resinhaving an excellent reactivity with a crosslinking agent and richflexibility by allowing to copolymerize with other radicallypolymerizable monomers. Further, it is useful for synthesizing aflexible multifunctional (meth)acrylate containing urethane bonds byallowing to react with polyisocyanates. Products prepared by the presentinvention can be utilized, in addition to the above-mentioned coating,as a material for a photocurable resin, a reactive diluent for thephotocurable resin, a flexibility agent for AS and ABS resins, anacrylic resin, a pressure sensitive adhesive, a flexible lens for aglass, an acrylic emulsion (particularly, a reaction type), a flexiblereactive diluent for an unsaturated polyester resin instead of styrene,and a polymerizable polyurethane elastomer, etc.

As the other radically polymerizable monomers to be copolymerized withthe polyester unsaturated monomer composition modified by a small amountof lactones of the present invention, there are enumerated an isocyanategroup-contained unsaturated monomer, a polymerizable monomer containingan active hydrogen, and other polymerizable unsaturated monomers.

As the other polymerizable unsaturated monomers, the following ones areenumerated.

As (meth)acrylates, for example, there are enumerated alkyl orcycloalkyl(meth)acrylates having a carbon number of 1-20 such asmethyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate,lauryl(meth)acrylate, cyclohexyl(meth)acrylate, isobonyl(meth)acrylate,adamantyl(meth)acrylate; and alkoxyalkyl(meth)acrylates having a carbonnumber of 2-8 such as methoxybutyl(meth)acrylate,methoxyethyl(meth)acrylate, and ethoxybutyl(meth)acrylate.

As monomers other than the (meth)acrylates, for example, there areenumerated glycidyl(meth)acrylate; styrene, -methylstyrene,vinyltoluene, (meth)acrylonitrile, (meth)acrolein, butadiene, andisoprene, etc., and these can be employed in mixing.

As a polymerizable monomer containing an active hydrogen, there areenumerated (meth)acrylates containing hydroxyl group, and(meth)acrylates containing amino group, etc., and these can be employedin mixing.

As the (meth)acrylates containing hydroxyl group, there are enumeratedhydroxyalkyl(meth)acrylates having a carbon number of 2-8 such ashydroxyethyl(meth)acrylate and hydroxypropyl (meth)acrylate, etc., andthese can be employed in mixing.

As the (meth)acrylates containing amino group, for example, there areenumerated an aminoalkyl(meth)acrylate such asdimethylaminoethyl(meth)acrylate and diethylaminoethyl(meth)acrylate;and (meth)acrylamide, etc., and these can be employed in mixing.

As monomers containing isocyanate group, for example, there areenumerated isocyanateethyl(meth)acrylate, isocyanatepropyl(meth)acrylate, isocyanatebutyl(meth)acrylate, isocyanatehexyl(meth)acrylate, m-isopropenyl-α,α′-dimethylbenzyl isocyanate, andm-ethylenyl-α,α′-dimethylbenzyl isocyanate, etc., and there isenumerated an unsaturated compound in which a polyisocyanate compoundsuch as hexamethylene diisocyanate is added to the polymerizable monomercontaining an active hydrogen such as hydroxyethyl(meth)acrylate, andthese can be employed in mixing.

The above-described radically polymerizable monomers can be alsoemployed in mixing, and those are selected depending upon desiredphysical properties.

The acrylic resin of the present invention is prepared by radicalpolymerization of the polyester unsaturated monomer modified by a smallamount of lactones of the present invention and the above-describedradically polymerizable monomers by publicly-known solutionpolymerization methods under the presence of radical polymerizationinitiators.

As the radical polymerization initiators, there can be employed aperoxide initiator such as benzoyl peroxide, t-butylhydroperoxide,cumylhydroperoxide, cumenhydroperoxide, t-butylperoxybenzoate, andt-butylperoxy-2-ethylhexanoate, and an azo-based initiator such asazobisisobutyronitrile and azobisdimethylvaleronitrile.

As solvents to be employed in the solution polymerization, for example,there are enumerated benzene, toluene, and xylene; an ester-basedsolvent such as butyl acetate, ethyl acetate, propyl acetate, andcellosolve acetate; an ether-based solvent such as dioxane andethyleneglycol dibutylether; and a ketone-based solvent such asmethylethylketone and methylisobutylketone, etc, and these can beemployed solely or in mixing of two or more kinds.

As a reaction apparatus to be employed in the above-describedpolymerization, there are preferably employed a reaction vessel equippedwith an agitator, a reflux condenser having a tube for drying and atwin-screw extruder.

Polymerization temperature and polymerization time of period depend upona kind of the polyester unsaturated monomer modified by a small amountof lactones of the present invention and the above-described radicallypolymerizable monomers, feeding ratio, a kind and amount of thecatalysts, and the apparatus, those are not particularly limited, andare appropriately decided depending upon uses of a desired acrylicresin, for example, physical properties in, for example, a coatinglayer.

There is obtained a unitary compound of the polyester unsaturatedmonomer modified by a small amount of lactones or a mixture having adifferent addition mol amount of ε-caprolactone from a reaction solutioncontaining thus-obtained polyester unsaturated monomer modified by asmall amount of lactones.

Structure of the polyester unsaturated monomer modified by a smallamount of lactones obtained can be identified and confirmed bymeasurement by an elementary analysis and a GPC analysis, of an acidvalue and double bond, etc.

According to the present invention, there can be prepared the polyesterunsaturated monomer modified by a small amount of lactones having anidentical radically polymerizable functional group to a radicallypolymerizable functional group contained in a radically polymerizableunsaturated monomer having carboxylic group in a short step and readilyin an industrial fashion. Since the polyester unsaturated monomermodified by a small amount of lactones obtained has one radicallypolymerizable unsaturated group, and carboxylic group at a terminal,there can be expected a wide range utilization as a raw material or anintermediate for a thermosetting coating, an adhesive, a crosslinkingagent, and an emulsion stabilizer, dispersant, and emulsifier for anemulsion, etc.

Further, in a composition in which the polyester unsaturated monomermodified by a small amount of lactones is employed, tackiness can beremoved by elevating Tg of the composition, and it is particularlyuseful in an electric material field, etc.

EXAMPLES

Hereinafter, although the present invention is illustrated by Examples,the present invention is not limited thereto.

It is to be noted that in the Examples, part and % are all based on theweight so far as particularly being defined.

I and II Example 1

A four-necked flask equipped with a tube for supplying air, athermometer, a condenser, and an agitating device was charged with 2446parts (18.8 mol) of 2-hydroxyethylmethacrylate (2-HEMA), 1610 parts(14.1 mol) of ε-caprolactone (ε-CL), 1.99 part of hydroquinonemonomethylether (HQME) which is a polymerization inhibitor, and 0.199part of stannous chloride (SnCl₂) which is a reaction catalyst, followedby allowing to react at 100° C. for 23 hour while streaming air.

Reaction ratio of -caprolactone was 99.4%, and color hue of a reactionproduct was 20 (APHA).

An excellent acrylic polyol resin was obtained by copolymerization of alactone-modified 2-hydroxyethylmethacrylate composition obtained withother monomers.

Example 2

A four-necked flask equipped with a tube for supplying air, athermometer, a condenser, and an agitating device was charged with 2446parts (18.8 mol) of 2-hydroxyethylmethacrylate (2-HEMA), 1610 parts(14.1 mol) of ε-caprolactone (ε-CL), 1.99 part of hydroquinonemonomethylether (HQME) which is a polymerization inhibitor, and 0.795part of monobutyltin tris-2-ethylhexanate which is a reaction catalyst,followed by allowing to react at 100° C. for 6.5 hour while streamingair. Reaction ratio of ε-caprolactone was 99.3% (cf. Table 2), and colorhue of a reaction product was 20 (APHA).

An excellent acrylic polyol resin was obtained by copolymerization of alactone-modified 2-hydroxyethylmethacrylate composition obtained withother monomers (cf. Example 5).

Example 3

A four-necked flask equipped with an tube for supplying air, athermometer, a condenser, and an agitating device was charged with 2446parts (18.8 mol) of 2-hydroxyethylmethacrylate (2-HEMA), 1073 parts (9.4mol) of ε-caprolactone (ε-CL), 1.72 part of hydroquinone monomethylether(HQME) which is a polymerization inhibitor, and 0.690 part ofmonobutyltin tris-2-ethylhexanate which is a reaction catalyst, followedby allowing to react at 100° C. for 7 hour while streaming air. Reactionratio of ε-caprolactone was 99.6%, and color hue of a reaction productwas 30 (APHA).

An excellent acrylic polyol resin was obtained by copolymerization of alactone-modified 2-hydroxyethylmethacrylate composition obtained withother monomers (cf. Example 6).

Example 4

The same apparatus as in the Example 1 was charged with 504 parts (3.8mol) of 2-hydroxyethylacrylate (2-HEA), 248 parts (2.2 mol) ofε-caprolactone, 0.368 part of hydroquinone monomethylether (HQME) whichis a polymerization inhibitor, and 0.148 part of monobutyltintris-2-ethylhexanate, followed by allowing to react at 100° C. for 7hour while streaming air. Reaction ratio of ε-caprolactone was 99.3%,and color hue of a reaction product was 25 (APHA).

An excellent acrylic polyol resin was obtained by copolymerization of acomposition obtained with other monomers (cf. Example 5).

Comparative Example 1

The same apparatus as in the Example 1 was charged with 2446 parts (18.8mol) of 2-hydroxyethylmethacrylate, 2146 parts (18.8 mol) ofε-caprolactone, 2.25 part of hydroquinone monomethylether which is apolymerization inhibitor, and 0.900 part of monobutyltintris-2-ethylhexanate which is a reaction catalyst, followed by allowingto react at 100° C. for 8 hour while streaming air. Reaction ratio ofε-caprolactone was 99.0%, and color hue of a reaction product was 25(APHA).

An excellent acrylic polyol resin was obtained by copolymerization of alactone-modified 2-hydroxyethylmethacrylate composition obtained withother monomers (cf. Comparative Example 7).

Comparative Example 2

The same apparatus as in the Example 1 was charged with 799 parts (6.1mol) of 2-hydroxyethylmethacrylate, 701 parts (6.1 mol) ofε-caprolactone, 0.735 part of hydroquinone monomethylether, and 0.147part of tetrabutyltitanate (TBT), followed by allowing to react at 100°C. for 64 hour while streaming air. Reaction ratio of -caprolactone was99.6%, and color hue of a reaction product was 50 (APHA).

It was not able to obtain an acrylic polyol resin by the samecopolymerization of a composition obtained with other monomers as inExample 5 because of an increased viscosity during reaction, and thengelation.

Comparative Example 3

The same apparatus as in the Example 1 was charged with 1816 parts (14.0mol) of 2-hydroxyethylmethacrylate, 3184 parts (27.9 mol) ofε-caprolactone, 2.50 part of hydroquinone monomethylether, and 1.00 partof monobutyltin tris-2-ethylhexanate, followed by allowing to react at100° C. for 8.5 hour while streaming air, and reaction ratio ofε-caprolactone was 99.2%, and color hue of a reaction product was 25(APHA).

An excellent acrylic polyol resin was obtained by copolymerization of alactone-modified 2-hydroxyethylmethacrylate composition obtained withother monomers (cf. Comparative Examples 9 and 10).

Comparative Example 4

The same apparatus as in the Example 1 was charged with 1816 parts (14.0mol) of 2-hydroxyethylmethacrylate, 4776 parts (41.8 mol) ofε-caprolactone, 3.30 part of hydroquinone monomethylether, and 1.32 partof monobutyltin tris-2-ethylhexanate, followed by allowing to react at100° C. for 8 hour while streaming air, and reaction ratio ofε-caprolactone was 99.2%, and color hue of a reaction product was 25(APHA).

An excellent acrylic polyol resin was obtained by copolymerization of alactone-modified 2-hydroxyethylmethacrylate composition obtained withother monomers (cf. Comparative Example 11).

Comparative Example 5

The same apparatus as in the Example 1 was charged with 1816 parts (14.0mol) of 2-hydroxyethylmethacrylate, 6364 parts (55.8 mol) ofε-caprolactone, 4.10 part of hydroquinone monomethylether, and 1.64 partof monobutyltin tris-2-ethylhexanate, followed by allowing to react at100° C. for 8.5 hour while streaming air, and reaction ratio ofε-caprolactone was 99.2%, and color hue of a reaction product was 30(APHA).

It is to be noted that theoretical addition mol number of ε-caprolactonein the Examples and Comparative Examples is as follows.

Example 1: n=0.75, Example 2: n=0.75, Example 3: n=0.50, Example 4:n=0.50, Comparative Example 1: n=1, Comparative Example 2: n=1,Comparative Example 3: n=2, Comparative Example 4: n=3, ComparativeExample 5: n=4

Product having n=0.5, product having n=0.75, product having n=1, producthaving n=2, and product having n=3 product having n=4 are shown asFM0.5, FM0.75, FM1, FM2, FM3, and FM4, respectively.

It is to be noted that FM shows a methacrylic acid series, and FA showsan acrylic acid series.

Table 1 and FIG. 1 show an ε-caprolactone continuous chain distributionin the compositions obtained from GPC, and % is GPC area %.

TABLE 1 0 0˜ ≧ ≧2 ≧3 CLM numbers (HEMA) 1 2 3 ≧4* >5 4 MV/Mn (%) (%)Reference Example 1 27.0 36.7 24.3 9.5 2.5 100.0 1.27 36.3 12.0Reference Example 2 26.3 36.3 24.5 9.6 3.3 100.0 1.24 37.4 12.9Reference Example 3 38.2 38.3 17.7 4.8 1.0 100.0 1.21 23.5 5.8 ReferenceExample 4 35.1 39.5 19.0 5.2 1.1 100.0 1.22 25.4 6.4 Reference 19.9 28.326.9 15.4 9.5 100.0 1.30 51.8 24.9 Comparative Example 1 Reference 6.216.7 25.9 23.2 15.7 12.3 87.7 1.28 77.1 51.2 Comparative Example 3Reference 3.1 8.1 17.0 21.9 20.7 29.3 70.7 1.28 88.8 71.8 ComparativeExample 4 Reference 1.4 3.9 9.9 16.4 19.6 48.9 51.1 1.26 94.8 84.9Comparative Example 5 *In the case that a peak by addition number of CLMof not less than 5 in small and cannot be separated from a peak havingnumber 4, it is shown by 4. In the Comparative Example 2, it was notable to conduct a measurement because of gelation.

Tables 2 and 3 collectively show a reaction composition, reactionconditions, and characteristics of reaction products in the Examples 1-4and Comparative Examples 1-5.

TABLE 2 Reference Example 1 2 3 4 Reaction Composition 2-HEMA (mol) 1 11 — 2-HEA — — — 1 ε-CL 0.75 0.75 0.5 0.5 HQME (ppm) 500 500 500 500SnCl₂ (ppm) 50 — — — MBTTH (ppm) — 200 200 200 TBT (ppm) — — — —Reaction Conditions Reaction Temperature (° C.) 100 100 100 100 ReactionTime of period (hrs) 23 6.5 7.0 7.0 Characteristics of Reaction Productε-CL reaction ratio (%) 99.4 99.3 99.6 99.3 Hydroxyl group value(mgKOH/g) 260 262 296 300 Acid value (mgKOH/g) 3.6 3.5 4.0 3.7 Color Hue(APHA) 20 20 30 25 Ethyleneglycol dimethacrylate 0.65 0.70 0.85 1.10 orEthyleneglycol diacrylate (%) [*MBTTH:Monobutyltintris-2-ethylhexanoate]

TABLE 3 Reference Comparative Example 1 2 3 4 5 Reaction Composition2-HEMA (mol) 1 1 1 1 1 2-HEA — — — — — ε-CL 1.0 1.0 2.0 3.0 4.0 HQME(ppm) 500 500 500 500 500 SnCl₂ (ppm) — — — — — MBTTH (ppm)* 200 — 200200 200 TBT (ppm) — 100 — — — Reaction Conditions Reaction Temperature100 100 100 100 100 (° C.) Reaction Time of period 8.0 6.4 8.5 8.0 8.5(hrs) Characteristics of Reaction Product ε-CL reaction ratio (%) 99.099.6 99.2 99.2 99.2 Hydroxyl group value 223 225 153 116 94 (mgKOH/g)Acid value (mgKOH/g) 3.7 3.7 2.7 2.0 1.7 Color Hue (APHA) 25 50 25 25 30Ethyleneglycol 0.35 3.96 0.28 0.20 0.15 dimethacrylate or Ethyleneglycoldiacrylate (%)

Example 5

A four-necked flask equipped with a thermometer, a reflux condenser, atube for supplying nitrogen gas, and an agitator was charged with 50parts of butyl acetate, 50 parts of toluene, and 1.0 part ofditertiarybutyl peroxide (DTBPO), followed by elevating a temperature to115° C. At a period having attained to 115° C., there were addeddropwise 17.3 parts of styrene, 17.3 parts of butylmethacrylate, 17.3parts of butylacrylate, 2.0 parts of methacrylic acid, 46 parts of theε-caprolactone-modified 2-hydroxyethylmethacrylate compositionsynthesized in the Example 2, 0 part of 2-hydroxyethylmethacrylate, and1.0 part of azobisisobutylnitrile over 3 hours, followed by continuing areaction for 4 hours to obtain an excellent acrylic polyol resintransparent liquid (a-1). Table 4 and Table 5 show composition of rawmaterials and characteristics of the resin solution, and Table 6 andFIG. 2 show a relationship between feeding ratio of ε-caprolactone/HEMAand a continuous chain distribution of ε-caprolactone.

Example 6 and Comparative Examples 6-11

In the same apparatus and formulating conditions as in the Example 5,there were polymerized the ε-caprolactone-modified acrylate compositionsobtained in the Example 3 and Comparative Examples 1-4 and HEMA.Although it was able to obtain an excellent acrylic polyol resintransparent liquid from the monomers obtained in the Example 3 andComparative Examples 3 and 4, in the case of the monomer obtained in theComparative Example 2, since a reaction liquid caused a viscosityincrease and gelation during polymerization, it was not able to obtain aresin solution.

Table 4 and Table 5 show composition of raw materials andcharacteristics of the resin solution in the respective Examples andComparative Examples, and Table 6 and FIG. 2 show a relationship betweenfeeding ratio of ε-caprolactone/HEMA and a continuous chain distributionof ε-caprolactone.

TABLE 4 Raw Reference Material Example Reference Comparative Example fed5 6 6 7 8 9 10 11 Butyl 50 50 50 50 50 50 50 50 acetate Toluene 50 50 5050 50 50 50 50 DTBPO 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Styrene 17.3 1923.3 15 17 7.0 15.8 16.3 Methyl 17.3 19 23.3 15 17 7.0 15.8 16.3methacrylate Butyl 17.3 19 23.3 15 17 7.0 15.8 16.3 methacrylateMethacrylic 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 acid Reference Example HEMAReference Comparative Example 2 3 used 1 1 3 3 4 ε-capro- 46 41 0 53.353.3 77 35.6 29.2 lactone- modified acrylic monomer HEMA 0 0 28 0 9.1 015 20 AIBN 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

TABLE 5 Reference Example Reference Comparative Example Acrylic poyolresin 5 6 6 7 8 9 10 11 solution a-1 a-2 RA-1 RA-2 RA-3 RA-4 RA-5 RA-6Char- acter- istics of Acrylic poyol resin solution Solid 50.1 51.1 50.050.0 50.6 50.5 50.3 51.1 content (%) Visc- 650 1210 550 560 800 750 6801120 osity (cp 25° C.) Color 35 35 30 30 30 30 35 35 hue (APHA) (based15.8 16.5 16.2 16.3 16.2 16.2 15.8 16.5 on sol- id) Acid value (mg-KOH/g) (based 120 123 120 118 118 121 120 120 on sol- id) Hy- droxylgroup value (mg- KOH/g) Tg 6 10 22 0 5 −19 1 2 (° C.)

TABLE 6 ε-caprolactone continuous chain ratio Continuous Distributionratio (%) (%) chain number→ 0 1 2 3 4 ≧5 ≧2 Reference Example 5 FM0.7526.3 36.3 24.5 9.6 3.3 0.0 37.4 6 FM0.5 38.3 38.3 17.7 4.8 1.0 0.0 23.5Reference Comparative Example  6 HBMA 100.0  7 FM1 19.9 28.3 26.8 15.49.5 0.0 51.8  8 FM1 + HEMA 31.6 24.2 22.9 13.2 8.1 0.0 44.2  9 FM2 6.216.7 25.9 23.2 15.7 12.3 77.1 10 FM2 + HEMA 34.0 11.8 18.2 16.3 11.0 8.754.2 11 FM3 + HEMA 42.5 4.8 10.1 13.0 12.3 17.4 52.7 *theabove-described FM-Number shows the feeding ratio ofε-caprolactone/HEMA.

In HEMA, the continuous chain distribution of ε-caprolactone is countedas 0.

In the polymerization of the acrylic polyol resins, OHV was set up at120 and Tg was set up at 0-10° C. in the Examples 5 and 6 andComparative Examples 7, 8, 9, and 10. As a result, it is confirmed thata proportion of a 1 mol adduct (n=1) of ε-caprolactone is high in theExamples 5 and 6, and there becomes low a proportion of adducts in which2 or more continuous chains of ε-caprolactone are added, and therelowers hardness in a melamine-cured product from the acrylic polyolresin.

In the case of employing a coating having a low proportion of theadducts in which 2 or more continuous chains of ε-caprolactone areadded, for example, as a top-coating material for cars, there can beobtained a coating layer which is well-balanced among a hardness of acoating layer, a finishing outer appearance, weatherability, acidresistance, staining resistance, gloss, flexibility, and abrasionresistance.

Example III

1. Preparation of a Clear Coating

A clear coating (series C) was prepared based on the formulation shownin Table III-7 described hereinafter.

A comparative clear coating (series SC) was prepared based on theformulation shown in Table III-7 described hereinafter.

2. Preparation of a Solid Color Coating

Preparation of a solid color coating was conducted by adding titaniumoxide to a mixture of a raw resin to be formulated with a melamine resinand dispersing by a motor mill (manufactured by Aiger Japan) for 30minutes, and adding residual components to be formulated. A solid colorcoating (series S) was prepared based on the formulation shown in TableIII-8 described hereinafter. A comparative solid color coating (seriesSR) was prepared based on the formulation shown in Table III-8 describedhereinafter.

Evaluation of Properties of a Coating

1. Preparation of Test Pieces

A test piece molded from a polyolefin-based resin (X50 manufactured byMitsui Kagaku) which is a body to be coated was washed byisopropylalcohol, and washed by a petroleum benzine.

2. Coating to a Test Piece

(1) In the Case of a Clear Coating

A primer (Primax No. 1500 manufactured by Nihon Yushi) was coated in 15m on the test piece and dried, and Primax No. 5500 (manufactured byNihon Yushi) was coated as a base coat coating.

Subsequently, a clear coating prepared as hereinabove was diluted by amixed thinner of xylene with Solvesso 100 as adjusted to 16 seconds inFord cup No. 4, followed by coating the clear coating onto the testpiece in wet-on-wet by air-spraying so that a dried coating layerbecomes 30 μm in the clear coating. After having placed for 10 minutesat a room temperature, it was dried by heating at 120° C. for 30 minutesand 100° C. for 30 minutes, and properties of the coating layer weremeasured after 24 hours. It is to be noted that a test in the case ofcoating a clear coating without using a primer is as follows. A basecoat coating X was prepared as described below, and diluted by a thinnerof toluene/ethyl acetate (weight ratio of 60/40) as adjusted to 13seconds in Ford cup No. 4, followed by air-spraying so that a driedcoating layer becomes 15 μm. Subsequently, a clear coating prepared ashereinabove was diluted by a mixed thinner of xylene with Solvesso 100as adjusted to 16 seconds in Ford cup No. 4, followed by coating theclear coating onto the test piece in wet-on-wet by air-spraying so thata dried coating layer becomes 30 μm in the clear coating. After havingplaced for 10 minutes at a room temperature, it was dried by heating at120° C. for 30 minutes and 100° C. for 30 minutes, and properties of thecoating layer were measured after 24 hours.

<Preparation of a Base Coat Coating X>

(a) Preparation of a Grafted Chlorinated Polyolefin Oligomer X havingPrimary Hydroxyl Groups

A four-necked flask equipped with an agitating device, a thermometer, atube for supplying an inert gas, a dropping funnel, and a reflux devicewas charged with 494 parts of toluene and 250 parts of Hardlene 14ML (achlorinated polyolefin manufactured by Toyo Kasei: chlorine content of26%), followed by temperature elevating to 100° C. while agitating.Subsequently, there was added dropwise a mixture composed of 142 partsof Placcel FM-3, 104 parts of isobonylmethacrylate, 6 parts ofbenzoylperoxide, and 4 parts of azobisisobutyronitrile over 3 hours, andreaction was further continued for 6 hours to obtain a graftedchlorinated polyolefin oligomer X.

(b) Preparation of a Base Coat Coating X

Formulation was conducted as follows.

Part Oligomer X 249 Super Bekkamine L-121-60 50 P-198 9 Butyl acetate 15Xylene 15 Tinuvin 384 3 Tinuvin 123 1.5 Aluminum paste 15 Modaflow 0.45

(2) In the Case of a Solid Color Coating

A primer was coated as being adjusted to the thickness of 15 μm as adried coating layer on the test piece and dried, followed by diluting asolid color coating prepared as hereinabove by a mixed thinner of xylenewith butyl acetate as being adjusted to 14 seconds in Ford cup No. 4,and followed by coating the clear coating onto the test piece by airspraying so that there becomes 30 μm a dried coating layer in the solidcolor coating. After having placed for 10 minutes at a room temperature,it was dried by heating at 120° C. for 30 minutes and 100° C. for 30minutes, and properties of the coating layer were measured after 24hours.

2. Evaluation Method of Properties

(1) Water Resistance Test

A molded article coated was partially immersed in warm water at 50° C.for 10 days. After having taken out, there was observed the presence orabsence of adhesion and a blister.

Herein, test pieces of many peeling or blisters were evaluated as x,test pieces of no peeling or slight blisters were evaluated as , andtest pieces of no causing peeling and blisters were evaluated as ◯.

(2) Gloss Retention Test

There was conducted an accelerating weatherability test bySunshine-weatherometer (manufactured by Suga Shikenki), and there wasmeasured a retention ratio (%) of a 60-mirror surface glossiness after1000 hours according to JIS K5400 (1979), and there was conducted anadhesion test according to JIS K5400 (1976) 6.15. Test pieces having thegloss retention ratio of not less tan 80% and excellent adhesion wereevaluated as, test pieces having the gloss retention ratio of not lessthan 70 and less than 80% and excellent adhesion were evaluated as, andtest pieces having the gloss retention ratio of less than 70% andpeeling in adhesion test were evaluated as x.

(3) Gasoline Resistance

A molded article coated was partially immersed in a regular gasoline(Nisseki Silver gasoline manufactured by Nihon Sekiyu) at 20° C. Afterhaving being taken out, a swelling property was visually evaluated. Testpieces showing remarkable swelling were evaluated as x, test piecesshowing slight swelling were evaluated as, and test pieces not showingswelling so much were evaluated as ◯.

(4) Acid Resistance Test

0.2 ml of 5%-sulfuric acid aqueous solution was dropped on a coatinglayer, followed by drying at 40° C. for 30 minutes and visuallyobserving a condition of the coating layer. Test pieces showing a markwere evaluated as x, test pieces slightly showing a mark were evaluatedas, and test pieces not showing a mark were evaluated as ◯.

(5) Solid Content in a Coating

In a coating having a lower solid content, it is more difficult toprepare a thick coating layer. In the clear coating and solid colorcoating, a coating having not more than 30% of solid content wasevaluated x, a coating having more than 30% and not more than 35% wasevaluated as, a coating having not less than 35% and not more than 40%were evaluated as ◯, and a coating exceeding 40% were evaluated as .

Data of properties are collectively shown in Tables III-7 to III-8.

TABLE 8 Example Comparative Example Clear coating C1 C2 C3 C4 SC-1 SC-2SC-3 SC-4 SC-5 SC-6 Formulation A-1 100 100 A-2 100 100 RA-1 100 RA-2100 RA-3 100 RA-4 100 RA-5 100 RA-6 100 Superbekkamine L-121-60 28 28 2828 28 28 28 28 28 28 (Dainippon Ink Kagaku Kogyo) Tinuvin 384 (CibaGeigy) 2 2 2 2 2 2 2 2 2 2 Sanol LS292 (Ciba Geigy) 1 1 1 1 1 1 1 1 1 1Ajitol XL122 (Hoechst) 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 P-198*(Dainippon 4 4 4 4 4 4 4 4 4 4 Ink Kagaku Kogyo) Xylol 24 24 24 24 24 2424 24 24 24 Sonolebetts 100 (Exon) 40 70 70 100 70 70 70 70 70 70Properties Glass transition temperature −10 −13 −7 −5 −3 −15 −10 −35 −10−13 (° C.) Weight average 13000 12500 13500 14000 12000 12500 1250013000 13500 12500 molecular weight Number average 8500 8500 8500 85008000 8300 8200 8200 8500 8200 molecular weight Mw/Mn 1.53 1.47 1.59 1.651.50 1.51 1.52 1.59 1.59 1.52 Amount of functional group 1.0 1.1 1.7 1.91.1 1.1 1.2 1.1 1.1 1.2 (mol/Kg resin) Type* of melamine resin B B B B BB B B B B Resin/melamine resin 79/21 ← ← ← ← ← ← ← ← ← Total acid value(mgKOH/g) 27 ← ← ← ← ← ← ← ← ← Characteristics 120° C., 30 minutes Solidcontent in a coating ⊚ ◯ ◯ Δ Δ ◯ ◯ ◯ ◯ ◯ Water resistance ◯ ◯ ◯ ◯ ◯ ◯ ◯Δ Δ Δ Gloss ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ Gasoline resistance ◯ ◯ ◯ ⊚ ◯ ◯ ◯ Δ Δ ΔAcid resistance ◯ ◯ ◯ Δ ⊚ Δ Δ X X X Abrasion resistance ◯ ◯ ◯ ◯ X ◯ ◯ ◯◯ ⊚ 100° C., 30 minutes Solid content in a coating ⊚ ◯ ◯ Δ Δ ◯ ◯ ◯ ◯ ◯Water resistance ◯ ◯ ◯ ◯ ◯ Δ Δ Δ Δ X Gloss ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ Δ Δ Gasolineresistance ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ Δ Δ Acid resistance ◯ ◯ ◯ ◯ ⊚ Δ Δ Δ X −XAbrasion resistance ◯ ◯ ◯ ◯ X ◯ ◯ ◯ ◯ ⊚ Note) P-198 is a mixed phosphate(manufactured by Dainippon Ink Kagaku Kogyo) composed of monobutylphosphate and dibutyl phosphate. Note) “A” in a type of a melamine resinmeans an imino type melamine resin. “B” in a type of a melamine resinmeans a methylol type melamine resin. Mn: Number average molecularweight Mw: Weight average molecular weight (hereinafter, the same alsoin Table 9)

TABLE 9 Solid color coating S1 S2 S3 S4 RS-1 RS-2 RS-3 RS-4 RS-5 RS-6Formulation A-1 166 166 A-2 166 166 RA-1 166 RA-2 166 RA-3 166 RA-4 166RA-5 166 RA-6 166 Superbekkamine 66 66 66 66 66 66 66 66 66 66 L-121-60P-198 6 6 6 6 6 6 6 6 6 6 Butyl acetate 120 160 160 180 Xylene 160 200200 200 200 ← ← ← ← ← Tinuvin 384 4 4 4 4 4 ← ← ← ← ← Sanol LS292 2 2 22 2 ← ← ← ← ← CR95 100 ← ← ← ← ← ← ← ← ← Modaflow (Monsant) 0.6 ← ← ← ←← ← ← ← ← Properties Glass transition −10 −13 −7 −5 −3 −15 −10 −35 −10−13 temperature (° C.) Weight average 13000 12500 13500 14000 1200012500 12500 13000 13500 12500 molecular weight Number average 8500 85008500 8500 8000 8300 8200 8200 8500 8200 molecular weight Mw/Mn 1.53 1.471.59 1.65 1.50 1.51 1.52 1.59 1.59 1.52 Amount of functional group 1.01.1 1.7 1.9 1.1 1.1 1.2 1.1 1.1 1.2 (mol/Kg resin) Type of melamineresin B B B B B B B B B B Resin/melamine resin 70/30 ← ← ← ← ← ← ← ← ←Total acid value 23 ← ← ← ← ← ← ← ← ← Characteristics 120° C., 30minutes Solid content in a coating ⊚ ◯ ◯ Δ Δ ◯ ◯ ◯ ◯ ◯ Water resistance◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ Δ Δ Gloss ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ Gasoline resistance ◯ ◯ ◯◯ ◯ ◯ ◯ Δ Δ Δ Acid resistance ◯ ◯ ◯ Δ ◯ Δ Δ X X X Abrasion resistance ◯◯ ◯ ◯ X ◯ ◯ ◯ ◯ ⊚ 100° C., 30 minutes Solid content in a coating ◯ ◯ ◯ ΔΔ ◯ ◯ ◯ ◯ ◯ Water resistance ◯ ◯ ◯ ◯ ◯ Δ Δ Δ Δ X Gloss ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ ΔΔ Gasoline resistance ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ Δ Δ Acid resistance ◯ ◯ ◯ ◯ ◯ Δ ΔΔ X X Abrasion resistance ◯ ◯ ◯ ◯ X ◯ ◯ ◯ ◯ ⊚

By the Examples and Comparative Examples, it is clear that there can beprepared a coating layer well-balanced among hardness of the coatinglayer, outer appearance in finishing, weatherability, acid resistance,staining resistance, glossiness, and abrasion resistance in the case ofemploying products having a low proportion of two or more continuouschains of ε-caprolactone as a material for a top coating in cars.

Example IV

In the hydroxyalkyl(meth)acrylate composition modified by a small amountof lactones obtained in the Example I, the composition obtained in theExample 2 is designated as (a-1), the composition obtained in theExample 3 is designated as (a-2), and the composition obtained in theExample 4 is designated as (a-3).

In the lactone-modified hydroxyalkyl(meth)acrylate composition obtainedin the Comparative Examples of the Example I, the composition obtainedin the Comparative Example 1 is designated as (a-1′), the compositionobtained in the Comparative Example 3 is designated as (a-2′), thecomposition obtained in the Comparative Example 4 is designated as(a-3′), and the composition obtained in the Comparative Example 5 isdesignated as (a-4′).

<Production of an Acrylic Polyol Resin (A) Solution>

Production Example IV-1

A four-necked flask equipped with a thermometer, an agitator, a refluxcondenser, an tube for supplying nitrogen gas was charged with 30 partsof ethyleneglycol monobutylether, followed by elevating a temperature to120° C. and maintaining.

In the flask, there was added dropwise a mixed solution of 31 parts ofstyrene, 21 parts of methylmethacrylate, 19 parts of 2-ethylhexylmethacrylate, 15 parts of the composition (a-1), 10 parts ofhydroxyethylmethacrylate, 4 parts of acrylic acid, and 10 parts of2,2′-azobisisobutyronitrile which is a polymerization initiator over 3hours. After that, aging was conducted at 120° C. for 1 hour and,subsequently, there was added dropwise a mixed liquid of 1 part of2,2′-azobisisobutyronitrile which is an additional polymerizationcatalyst and 10 parts of ethyleneglycol monobutylether over 1 hour,aging was further conducted for 3 hours to obtain an acrylic polyolresin (A-1) solution having a solid content of approximately 71%.

In the resin (A-1) obtained, an acid value was 30, a weight averagemolecular weight (by GPC, hereinafter, the same) was approximately9,500, and a glass transition temperature was 45° C.

Production Examples IV-2 to IV-3

The same procedures were conducted as in the Production Example IV-1,except that the composition (a-1) to be added dropwise was changed tothe composition (a-2) or the composition (a-3) to obtain an acrylicpolyol resin (A-2) solution or (A-3) solution.

Production Examples IV-4 to IV-7 (for references)

The same procedures were conducted as in the Production Example IV-1,except that the composition (a-1) to be added dropwise was changed to2-hydroxyethylmethacrylate (HEMA) or the (a-1′)-(a-4′) in the ReferenceComparative Examples to obtain acrylic polyol resin (A-1′)-(A-4′)solutions for references.

Production Example IV-8

Production Example of Other Acrylic Resin (A#) Solution

A four-necked flask equipped with a thermometer, an agitator, a refluxcondenser, an tube for supplying nitrogen gas was charged with 30 partsof ethyleneglycol monobutylether, followed by elevating a temperature to90° C. and maintaining.

Into the flask, there was added dropwise a mixed solution of 35 parts ofn-butylacrylate, 30 parts of 2-ethylhexyl methacrylate, 30 parts ofN-n-butoxymethylmethacrylic amide, and 5 parts of acrylic acid, and 6parts of benzoyl peroxide which is a polymerization initiator over 3hours. After that, aging was conducted at 90° C. for 5 hour to obtain anacrylic resin (A#) solution having a solid content of approximately 77%.In the acrylic resin (A#) obtained, an acid value was 39, a weightaverage molecular weight was approximately 10,000, and a glasstransition temperature was −21° C.

Table IV-7 shows formulation ratio in the Production Examples IV-1 toIV-7 and physical properties of the resins obtained.

Table IV-8 shows formulation ratio in the Production Example IV-8 andphysical properties of the resins obtained.

It is to be noted that the physical properties were measured accordingto the following methods.

Acid value in the resins: Sample was dissolved in a mixed solution ofethanol and toluene, and it was measured by a neutralizing titration of0.1N solution of potassium hydroxide-ethanol using phenolphthalein as anindicator.

Weight average molecular weight: It was measured according to JISK0124-83. Using TSK GEL G4000+G3000+G2500+G2000 (manufactured by ToyoSoda, Ltd.) as a column for separation, a measurement was conducted at40° C. and a flow rate of 1.0 mm/minute, and it was calculated by acalibration curve prepared by a chromatogram obtained by an RIrefractometer and a standard Polystyrene using tetrahydrofran for GPC asan eluate.

Glass transition temperature (Tg point): Using a differential scanningcalorimeter DSC-50Q (Shimadzu Seisakusyo, Ltd.), it was measured fromthermal spectra obtained in temperature elevation rate of 5° C./minute.

In the following Tables, IV is omitted.

Production No. 1 2 3 4 5 6 7 Mixed solution added dropwise Acrylic poyolresin A-1 A-2 A-3 A-4 A-5 A-6 A-7 2-ethylhexylmethacrylate 19 ← ← ← ← ←← Lactone-modified methacrylate a-1:15 a-2:15 a-3:15 — a-1′:15 a-2′:15a-3′:15 2-hydroxyethylmethacrylate 10 ← ← 25 ← ← ← Acrylic acid 4 ← ← ←← ← ← Styrene 31 ← ← ← ← ← ← Methylmethacrylate 21 ← ← ← ← ← ←2,2′-azobisisobutylnitrile 1 ← ← ← ← ← ← Physical properties Resin acidvalue 31 31 32 33 30 30 31 Weight average molecular weight 8500 90008700 9000 8800 8600 9000 Glass transition 47 45 43 50 42 40 39temperature (° C.) Production No. 8 Mixed solution added dropwiseAcrylic resin A# N-butoxymethylacrylate 30 Acryli acid 52-ethylhexylmethacrylate 30 N-butylacrylate 35 Benzoyl peroxide 6Physical properties Resin acid value 40 Weight average molecular weight8500 Glass transition 47 temperature (° C.)

Example IV-1

3.1 parts (amount corresponding to 1.0 mol with respect to 1 mol ofcarboxylic group in the acrylic resin) of N,N-dimethylaminoethanol wasadded to 70 parts of the acrylic polyol resin (A-1) solution having asolid content of approximately 71% obtained in the Production ExampleIV-1 and 13 parts of the acrylic resin (A#) solution having a solidcontent of approximately 77% obtained in the Production Example IV-8,followed by uniformly mixing at 50° C. and, followed by adding 50 partsof Nikalak N-6215 (a methyletherized methylolmelamine-benzoguanaminecocondensed resin manufactured by Sanwa Chemical, Ltd.) as anaminoplasto resin (IV-B) and 0.7 part of Nacure (Nacure) 5225 (a curingcatalyst manufactured by King Industries, Ltd., USA). After havingsufficiently mixed at 30° C., deionized water was gradually added toprepare a water-based coating having a solid content of approximately40%.

Examples IV-2 to IV-3 and Comparative Examples IV-1 to IV-4

The same procedures were conducted as in the Example IV-1, except thatrespective acrylic polyol resin solutions, aminoplasto resin (IV-B), andformulation amount (solid content) of the resins were changed as shownin Table IV-9, and amount of N,N-dimethylaminoethanol were changed to anamount corresponding to 1.0 mol with respect to 1 mol of carboxylicgroup in the acrylic resin to be employed to prepare a water-basedcoating.

<Preparation of a Test Plate to be Coated>

A commercially supplied ink was coated on an aluminum plate having thethickness of 0.3 mm, and respective water-based coatings obtained in theExamples and Comparative Example were coated by wet-on-wet so thatthickness of a coating layer becomes 5 m after having dried,subsequently, baking was conducted for 90 seconds at a condition inwhich a maximum temperature being capable of attaining in materialsbecomes 200° C. to obtain a coated plate. It is to be noted that it wasnot able to coat the coatings in the Comparative Example 2 andComparative Example 9 because of a high viscosity.

In relation to thus-obtained coated plate, there were tested physicalproperties of the coating layer and a wet ink-adaptability. Test resultsare shown in Table IV-9.

Tests were conducted according to the methods described below.

Pencil Hardness: A pencil scratch test regulated in JIS K5400 8. 4.2(1990) was conducted on the coated plate, and evaluated by scratches.

Retort resistance: A coated plate was immersed in a deionized water. Awhitening condition of the coated layer and the pencil hardness werechecked after having treated for 30 minutes at 125° C. in an autoclave.

The whitening condition of the coated layer was visually evaluatedaccording to the following rules.

: quite no whitened

◯: slightly whitened

 : very whitened

x: whitened at all surface

After the coated plate was pulled up from water and placed in warm waterof 80° C. for 3 minutes, the pencil scratch test was conducted in warmwater of 80° C. according to JIS K-5400 8. 4. 2 (1990), and the coatedlayer was evaluated by scratches.

Processability: Test in relation to the coated plate was conducted atconditions of drop weight of 300 g, an edge diameter in a striking pinof ½ inch, and drop height of 20 (cm) according to a Dupon't styleimpact test by JIS K5400 8. 4. 2 (1990). Cracks of the coated layer werevisually observed at an impact portion and a periphery thereof.

: Cracks are not observed.

◯: Cracks are slightly observed.

 : Cracks are very observed at an impact portion.

x: Cracks are very observed also at a periphery of an impact portion.

Adhesion: 100 pieces of cross-hatches of 1 mm×1 mm were made on thecoated plate according to a cross-hatched test by JIS K-5400 8. 5. 2(1990), and a cellophane tape was stuck on the surface, and it wasevaluated by counting the number of the cross-hatches remained afterhaving abruptly stripped.

100 means that the coated layer was not stripped at all.

Wet ink adaptability: Finishing outer appearance of the coated plate wasobserved.

TABLE IV-9 Example No. 1 2 3 4 5 6 7 Acrylic poyol resin A-1 A-2 A-3A-1′ A-2′ A-3′ A-4′ amount 50 ← ← ← ← ← ← Acrylic resin A# ← ← ← ← ← ←amount 10 ← ← ← ← ← ← Amino plasto resin 40 ← ← ← ← ← ← Nikalak-N-6215Properties of coating layer Pencil hardness 4H 4H 4H 4H 3H 2H 2H Retortproperty: ⊚ ⊚ ⊚ ⊚ ◯ ◯ Δ whitening Pencil hardness 2H 2H 2H 2H H HB BProcessability ◯ ⊚ ⊚ Δ ⊚ ⊚ ⊚ Adhesion 100 100 100 80 100 100 100 Wet inkadaptability ⊚ ⊚ ⊚ Δ ⊚ ⊚ ⊚

It is confirmed that the melamine-curable water-based coatingcomposition is excellent in physical properties of the coating layer andwetting adaptability, which is composed of an acrylic polyol resin (A)obtained using the above-described hydroxyethyl(meth)acrylatecomposition (a) modified by a small amount of lactones and theaminoplasto resin (IV-B).

Example V

1. Preparation of a Coating

In a coating (C series) and a comparative coating (SC series), therewere employed a resin (A-1) obtained in Reference Example 5 and a resin(A-2) obtained in Reference Example 6 which are shown in Table 5, andrespective resins (RA-1)-(RA-6) obtained in Comparative ReferenceExamples 6-11.

These acrylic polyol resins (A-1)-(RA-6) were formulated with thefollowing substances to obtain a coating.

part Acrylic polyol resin 100 Super Bekkamine L-121-60 28 P-198 9 Butylacetate 15 Xylene 15 Tinuvin 384 3 Tinuvin 123 1.5 Modaflow 0.45

In the above descriptions, P-198 (manufactured by Dainippon Ink, Ltd.)is a mixture of monobutyl phosphate with dibutyl phosphate.

A white enamel base was obtained by kneading for 60 minutes in a sandmill based on the above-described formulation, and an acrylic urethanecoating was prepared by formulating a desired amount of a curing agent.

2. Formulation of a Multi-Layered Type Elastic Acrylic Emulsion Coating

part Boncoat 3663 432.0 Demor EP (Kao Atlas) 6.0 Ethyleneglycol(Mitsubishi Kagaku) 4.3 Adekanate B-187 (Asahi Denka) 13.0 CelltopHP-103 (Teikoku Kako) 4.3 Calcium carbonate NS-100 (Nitto Funka) 380.5ASP-600 (ENGEL HARD) 67.7 Taipe R-550 (Ishihara Sangyo) 13.0 5%Highmetrose 90 SH-1500 (Shin-etsu Kagaku) 28.9 Adekanol UH-420 (AsahiDenka) 2.7 water 47.6 Total 1,000.0

Evaluation of Properties of a Coating

1. Preparation of a Test Piece

As a test piece, a test piece molded from a polyolefin-based resin (X50manufactured by Mitsui Kagaku) was washed by isopropylalcohol, andwashed by a petroleum benzine.

2. Coating onto a Test Piece

(1) A primer (Primax No. 1500 manufactured by Nihon Yushi) was coated in15 μm onto the test piece and dried, and Primax No. 5500 (manufacturedby Nihon Yushi) was coated as a base coating.

Subsequently, a clear coating prepared as hereinabove was diluted by amixed thinner of xylene and Solvesso 100 as being adjusted to 16 secondsin Ford cup No. 4, followed by coating the clear coating onto the testpiece in wet-on-wet by air-spraying so that a dried coating layerbecomes 30 μm in the clear coating. After having placed for 10 minutesat a room temperature, it was dried by heating at 120° C. for 30 minutesand 100° C. for 30 minutes, and properties of the coating layer weremeasured after 24 hours. It is to be noted that a test in the case ofcoating a clear coating without using a primer is as follows. A basecoat coating X was diluted by a thinner of toluene/ethyl acetate (weightratio of 60/40) as being adjusted to 13 seconds in Ford cup No. 4,followed by air-spraying so that a dried coating layer becomes 15 μm.

Subsequently, respective coatings prepared as hereinabove were dilutedby a mixed thinner of xylene and Solvesso 100 as being adjusted to 16seconds in Ford cup No. 4, followed by coating the clear coating ontothe test piece in wet-on-wet by air-spraying so that a dried coatinglayer becomes 30 μm in the clear coating. After having placed for 10minutes at a room temperature, it was dried by heating at 120° C. for 30minutes and 100° C. for 30 minutes, and properties of the coating layerwere measured after 24 hours.

Preparation of a Base Coat Coating X

(a) Preparation of a Grafted Chlorinated Polyolefin Oligomer X having aPrimary Hydroxyl Group

A four-necked flask equipped with an agitating device, a thermometer, antube for supplying an inert gas, a dropping funnel, and a reflux devicewas charged with 494 parts of toluene and 250 parts of Hardlene 14ML (achlorinated polyolefin manufactured by Toyo Kasei: chlorine content of26%), followed by temperature elevating to 100° C. while agitating.Subsequently, there was added dropwise a mixture composed of 142 partsof Placcel FM-3, 104 parts of isobonylmethacrylate, 6 parts ofbenzoylperoxide, and 4 parts of azobisisobutyronitrile over 3 hours, andreaction was further continued for 6 hours to obtain the above-describedgrafted chlorinated polyolefin oligomer X.

(b) Preparation of a Base Coat Coating X

Formulation was conducted as follows.

Part Oligomer X 249 Super Bekkamine L-121-60 50 P-198 9 Butyl acetate 15Xylene 15 Tinuvin 384 3 Tinuvin 123 1.5 Aluminum paste 15 Modaflow 0.45

2. Evaluation Method of Properties

(1) Water Resistance Test

A molded article coated was partially immersed in warm water at 50° C.for 10 days. After having taken out, there was observed the presence orabsence of adhesion and a blister.

Herein, test pieces having many peeling or blisters were evaluated as x,test pieces not having peeling or having slight blisters were evaluatedas, and test pieces not causing peeling and blisters were evaluated as◯.

(2) Gloss Retention Test

There was conducted an accelerating weatherability test bySunshine-weatherometer (manufactured by Suga Shikenki), there wasmeasured a retention ratio (%) of a 60-mirror surface glossiness after1000 hours according to JIS K5400 (1979), and there was measured anadhesion test according to JIS K5400 (1976) 6.15. Test pieces havinggloss retention ratio of not less tan 80% and excellent adhesion wereevaluated as ◯, test pieces having gloss retention ratio of not lessthan 70 and kess than 80% and excellent adhesion were evaluated as andtest pieces having gloss retention ratio of less than 70% and peeling inadhesion test were evaluated as x.

(3) Gasoline Resistance

A molded article coated was partially immersed in a regular gasoline(Nisseki Silver gasoline manufactured by Nihon Sekiyu) at 20° C. Afterhaving taken out, a swelling property was visually evaluated. Testpieces showing remarkable swelling were evaluated as x, test piecesshowing slight swelling were evaluated as, and test pieces not showingswelling so much were evaluated as ◯.

(4) Acid Resistance Test

0.2 ml of 5%-sulfuric acid aqueous solution was dropped on a coatinglayer, followed by drying at 40° C. for 30 minutes and visuallyobserving a condition of the coating layer. Test pieces showing markswere evaluated as x, test pieces slightly showing marks were evaluatedas and test pieces not showing marks were evaluated as ◯.

(5) Solid Content in a Coating

In a lower solid content in a coating, it is more difficult to prepare athick coating layer. In the clear coating and solid color coating, acoating having not more than 30% of solid content was evaluated x, acoating having not less than 30 and not more than 35% were evaluated asΔ, a coating having not less than 35 and not more than 40% wereevaluated as ◯, and a coating exceeding 40% were evaluated as .

(6) Pot Life

It was measured according to JIS K5400 (1999) 4.9.

Physical properties of a coating layer were measured as follows.

Coating: An acrylic urethane coating obtained was diluted by a solventof xylene/butyl acetate=60/40 to a viscosity being capable of coating,and spray-coated onto respective base materials so that layer thicknessbecomes 70-75 μm after drying. Curing for drying was conducted byplacing at a room temperature for 2 weeks.

(7) Extension, Tensile Strength Test: An acrylic urethane coating asprepared hereinabove was coated on an acrylic emulsion dried coatinglayer having a layer thickness of approximately 1 mm prepared using anelastic acrylic emulsion coating obtained hereinabove, and it was driedat an ordinary temperature for 2 weeks to prepare a coating layer. Usingthe coating layer, measurement was conducted according to JIS A6910(1984) 5. 13.

(8) Deterioration Test in Extension: Measurement was conducted accordingto JIS A6910 (1984) 5. 13 using a multi-layered coating layer preparedin the (7).

(9) Adhesion Strength: Measurement was conducted according to JIS A6910(1984) 5. 8 using a multi-layered coating layer prepared in the (7).

(10) Cold Cycle Test: It was conducted according to JIS A6910 (1984) 5.9

(11) Dispersibility of Pigments

(A Monochromatic Base)

carbon black:

Royal Sbectramark I (Columbia Carbon, Ltd.) PWC5%

Shinkasya Red:

Fastogen Super Red BN (Dainippon Ink Kagaku, Ltd.) PWC10%

Dianine Blue:

Fastogen Blue FGS (Dainippon Ink Kagaku, Ltd.) PWC10%

Coagulation property and a thixotropic property were visually judged inrelation to an original color enamel base kneaded under specialconditions.

(Mixed Color Base)

The above-described respective color enamel bases were formulated sothat it becomes white/original color=98/2 (pigments ratio), and a curingagent was formulated. After having diluted by a solvent, it was spraycoated. After having confirmed dryness by finger touch, the same coatingpartially remained was flow-coated on an approximately half portion inthe coated plate and cured.

Quality of dispersibility was judged by a color difference (E) between aspraying portion and flow coating portion. Smaller value is moreexcellent in dispersibility.

(12) Staining Resistance:

(i) Staining by a Felt Pen:

After having been stained by a felt pen, sample was placed at roomtemperatures for 2 hours, and wiped by a solvent ofpetroleum/ethanol=1/1, and a staining level was visually judged.

Herein, ◯: Marks are not quite remained. ◯: Marks are slightlyremained.: Marks are fairly remained. x: Marks are very remained.

(ii) Staining by Wet Carbon:

Water dispersion containing 3% of carbon was made, and it was softlyapplied by cotton, and it was placed at an ordinary temperature for 1day. After having washed by water, marks were visually judged.

Rules for judgement are the same as in the (i).

From the Examples and Comparative Examples, it is evident that in thecase that a coating having a low proportion of the adducts in which notless than 2 mol of ε-caprolactone is added is employed as, for example,a top-coating material for cars, there can be obtained a coating layerwhich is well-balanced among excellent workability, a hardness of acoating layer, a finishing outer appearance, weatherability, acidresistance, staining resistance, gloss, flexibility, and abrasionresistance.

Example VI Reference Example VI-7 [Preparation Example of a Copolymer(VIA-1)]

A four-necked flask replaced with nitrogen gas was charged with 294parts of methylethylketone, followed by maintaining at 75° C. whileagitating. Subsequently, there was added dropwise a mixture composed of36.9 parts of methacrylic acid, 90.0 parts of styrene, 42.6 parts ofbutyl acrylate, 40.5 parts of an ε-caprolactone-modified acrylic monomerobtained in the Example 1, 90.0 parts of lauryl methacrylate, and 6.0parts of Perbutyl O [tert-butylperoxy-2-ethylhexanoate manufactured byNihon Yushi, Ltd.] over 2 hours. Further, reaction was conducted at thesame temperature for 5 hours to obtain a copolymer (VIA-1) havingnonvolatile components of 50.0% by weight, an acid value of 80 and,further, hydroxyl value of 58 (unit: mg-KOH/g, hereinafter, the same).

Reference Example VI-8 [Preparation Example of a Copolymer (VIA-2)]

A four-necked flask replaced with nitrogen gas was charged with 870parts of methylethylketone, followed by maintaining at 80° C. whileagitating. Subsequently, there was added dropwise a mixture composed of207 parts of styrene, 150 parts of lauryl methacrylate, 72 parts of anε-caprolactone-modified acrylic monomer obtained in the Example 3, 168parts of butyl methacrylate, and 30 parts of “Perbutyl O” over 4 hours.Further, polymerization reaction was continued over 4 hours whileagitating to obtain a resin having hydroxyl groups, which has a numberaverage molecular weight of 26,000 and nonvolatile components of 40%.

Subsequently, 6.8 parts of methacrylic anhydride was added to thepolymer solution, followed by agitating for 4 hours to obtain a vinylgroup-modified resin (VIB-1) having hydroxyl groups. After that, thesame flask as in the above-described flask was charged with 175 parts ofthe resin (VIB-1), followed by elevating temperature to 80° C. whileagitating. There was added dropwise a mixture of 9.2 parts by weight ofmethacrylic acid, 7.6 parts of styrene, 7.5 parts of laurylmethacrylate, 3.4 parts of butyl acrylate, 2.3 parts of 2-hydroxyethylmethacrylate, 4.5 parts of “Perbutyl O”, and 20 parts by weight ofmethylethylketone over 4 hours to allow to continue a polymerization.

Also after that, agitation was allowed to continue over 2 hours toobtain a vinyl-based copolymer (VIA-2). Non volatile components were45.6%.

Reference Example VI-9 [Preparation Example of a Copolymer (VIA-3)]

A reaction vessel replaced with nitrogen was charged with 870 parts ofmethylethylketone, followed by elevating a temperature to 80° C. whileagitating. Into the vessel, there was added dropwise a mixture composedof 180 parts of styrene, 150 parts of lauryl methacrylate, 78 parts ofbutyl acrylate, 72 parts of an ε-caprolactone-modified acrylic monomerobtained in the Example 3, 120 parts of glycidyl methacrylate, and 30parts of “Perbutyl O” over 4 hours to allow to continue polymerization.Further, agitation was continued over 4 hours to obtain a polymersolution of a resin having glycidyl groups and hydroxyl groups, whichhas a number average molecular weight of 20,000 and nonvolatilecomponents of 40%.

Subsequently, 6.8 parts of methacrylic anhydride was added to thepolymer solution, followed by agitating at 60° C. for 6 hours and adding0.5 part of water to obtain a vinyl-modified resin (VIB-2) havinghydroxyl groups, in which glycidyl groups are remained.

After that, the same vessel as in the above-described vessel was chargedwith 300 parts of the resin (VIB-2), followed by elevating temperatureto 80° C. while agitating.

Subsequently, there was added dropwise a mixture composed of 39.2 partsof methacrylic acid, 27.0 parts of styrene, 45.0 parts of laurylmethacrylate, 41.0 parts of butylacrylate, 27.8 parts of 2-hydroxyethylmethacrylate, 27.0 parts of “Perbutyl O”, and 40.0 parts by weight ofmethylethylketone over 4 hours to allow to conduct a polymerization.Also after that, agitation was allowed to continue over 2 hours toobtain a vinyl-based copolymer (VIA-3). Non volatile components were54.8%.

Reference Example VI-10 [Preparation Example of a Copolymer (IVA-4)]

A reaction vessel replaced with nitrogen was charged with 150 parts ofthe resin (VIB-1) obtained in the Reference Example IV-8 and the resin(VIB-2) obtained in the Reference Example VI-10, respectively, followedby elevating temperature to 80° C. while agitating.

Subsequently, there was added dropwise a mixture composed of 39.2 partsof methacrylic acid, 27.0 parts of styrene, 45.0 parts of laurylmethacrylate, 41.0 parts of butylacrylate, 27.8 parts of 2-hydroxyethylmethacrylate, 27.0 parts of “Perbutyl O”, and 40.0 parts by weight ofmethylethylketone over 4 hours to allow to conduct a polymerization.Also after that, agitation was allowed to continue over 2 hours toobtain a vinyl-based copolymer (VIA-4). Non volatile components were54.8%.

Reference Example VI-11 [Preparation Example of a Copolymer (VIA-5)]

A reaction vessel was charged with 62.5 parts of a polycaprolactone diolhaving a number average molecular weight of 1,250, 167.8 parts of “AOGX68” [a long chain olefin glycol manufactured by Daicel ChemicalIndustries, Ltd., hydroxyl value=290], and 111 parts of1-isocyanate-3-isocyanatemethyl-3,5,5-trimethylcyclohexane (IPDI), andtemperature was elevated to 110° C. under nitrogen atmosphere whileagitating, followed by maintaining at the temperature for 60 minutes.

After that, the temperature was decreased to 80° C., and there were fed33.5 parts of dimethylol propionic acid, 160.6 parts of ethyl acetate,and 0.05 part of tin octoate, followed by allowing to continue areaction at 75° C. for 7 hours. After the completion of the reaction,214.2 parts of ethyl acetate was added to obtain a urethane resinsolution having hydroxyl groups which has non volatile components of50%.

2.6 parts of methacrylic anhydride was fed into the resin solution,followed by agitating at 75° C. for 4 hours to obtain a vinyl-modifiedresin (VIB-3) having hydroxyl groups.

Subsequently, 100 parts of the resin (VIB-3) was fed into a samereaction vessel replaced with nitrogen, followed by elevating atemperature to 75° C. while agitating. There was added dropwise amixture composed of 15.4 parts of methacrylic acid, 23.3 parts ofstyrene, 22.4 parts of isobutyl methacrylate, 5.5 parts of2-hydroxyethyl methacrylate, 50.1 parts of the -caprolactone-modifiedacrylic monomer obtained in the Reference Example 3, 9.3 parts of “NiperBW” [benzoyl peroxide manufactured by Nihon Yushi, Ltd.], and 116.7parts of ethyl acetate over 4 hours to allow to conduct a polymerizationreaction. Also after that, agitation was allowed to continue over 4hours to obtain a vinyl-based copolymer (VIA-5). Nonvolatile componentswere 48.6%.

Reference Comparative Example VI-12 [Preparation Example of a Copolymer(VIRA-1)]

The same polymerization was followed as in the Reference Example VI-7except that the ε-caprolactone-modified acrylic monomer obtained in thecomparative Example 1 was employed in place of 40.5 parts of theε-caprolactone-modified acrylic monomer obtained in the Example 1 toobtain a vinyl-based copolymer having non volatile components of 50.0%,an acid value of 80, and a hydroxyl value of 58.

Reference Comparative Example VI-13 [Preparation Example of aVinyl-Based Copolymer (VIRA-2)]

The same polymerization was followed as in the Reference Example VI-11except that “Placcel FM3” [a lactone-modified hydroxyethylmethacrylatemanufactured by Daicel Kagaku Kogyo, Ltd.] was employed in place of theε-caprolactone-modified acrylic monomer obtained in the ComparativeExample 3 to obtain a vinyl-based copolymer having non volatilecomponents of 50.0%, an acid value of 80, and a hydroxyl value of 58.

Example VI-1

In a reaction vessel which is vigorously agitated there were mixed 200parts of the vinyl-based copolymer (VIA-1) which is an acrylic polyolresin, 39.7 parts of “Vernok 980” [a polyisocyanate manufactured byDainippon Ink Kagaku Kogyo, Ltd., nonvolatile components=75.6%], 100parts of methylethylketone, and 5.0 parts of triethylamine, and 300parts of distilled water was gradually added to the vessel. During areaction, 0.02 part of dibutyltin dilaurate was added immediately beforephase inversion, and 200 parts of distilled water was added after phaseinversion.

Subsequently, solvents were distilled off at reduced pressure, andheating was continued at 60° C. for 1 hour to allow to accelerate acrosslinking in inside of particles. After that, water was partiallydistilled off at reduced pressure to obtain a water dispersion ofcrosslinked particles having 31.0% of nonvolatile components.

After that, the water dispersion of crosslinked particles was partiallytaken out, and tetrahydrofran was added in a 100 times amount and, as aresult, it was muddy without transparently dissolving.

Further, the water dispersion was maintained at 50° C. for 20 days, anda change was observed with a lapse of time and, as a result, any changewas not observed in stability of dispersibility.

However, when ethyleneglycol monobutylether was added in an amountcorresponding to 20% based on solid components in the water dispersion,tendency of viscosity increase was observed in a system after 20 days at50° C.

It is to be noted that it showed an average molecular weight of 570between crosslinking points in thus-obtained crosslinked particles,which is a designed value. Still further, a solvent was added in anamount corresponding to 20% based on solid components and, as a result,a film-forming temperature was not more than a room temperature.

Example VI-2

The same procedures were followed as in the Example IV-1, except thatthere were employed 219.3 parts of the vinyl-based copolymer (VIA-2)which is an acrylic polyol resin, 39.7 parts of “Vernok 980”, 100 partsof methylethylketone, and 10.8 parts of triethylamine. As a result,nonvolatile components were 31.6% in thus-obtained water dispersion ofcrosslinked particles and a dispersion state was also excellent.

Subsequently, the water dispersion of crosslinked particles waspartially taken out, and tetrahydrofran was added in a 100 times amountand, as a result, it was muddy without transparently dissolving.Further, the water dispersion was maintained at 50° C. for 20 days, anda change was observed with a lapse of time and, as a result, any changewas not observed in stability of dispersibility. Likewise, whenethyleneglycol monobutylether was added in an amount corresponding to20% based on solid components in the water dispersion, tendency ofviscosity increase was not observed in a system even after 20 days at50° C. It is to be noted that it showed an average molecular weight of630 between crosslinking points in thus-obtained crosslinked particles,which is a designed value. Still further, a solvent was added in anamount corresponding to 20% based on solid components and, as a result,a film-formable temperature was not more than a room temperature.

Example VI-3

The same procedures were followed as in the Example IV-1, except thatthere were employed 182.5 parts of the vinyl-based copolymer (VIA-3)which is an acrylic polyol resin, 26.5 parts of “Vernok 980”, 150 partsof methylethylketone, and 15.3 parts of triethylamine. As a result,nonvolatile components were 30.5% in thus-obtained water dispersion ofcrosslinked particles and a dispersion state was also excellent.

Subsequently, the water dispersion of crosslinked particles waspartially taken out, and tetrahydrofran was added in a 100 times amountand, as a result, it was muddy without transparently dissolving.Further, the water dispersion was maintained at 50° C. for 20 days, anda change was observed with a lapse of time and, as a result, any changewas not observed in stability of dispersibility. Likewise, whenethyleneglycol monobutylether was added in an amount corresponding to20% based on solid components in the water dispersion, tendency ofviscosity increase was not observed in a system even after 20 days at50° C. It is to be noted that it has an average molecular weight rangingin 510-680 between crosslinking points in the crosslinked particles,which is a designed value, and which only slightly changes throughreaction between glycidyl groups.

Still further, a solvent was added in an amount corresponding to 20%based on solid components and, as a result, a film-forming temperaturewas not more than room temperatures.

Example VI-4

The same procedures were likewise followed as in the Example IV-1,except that there were employed 182.5 parts of the vinyl-based copolymer(VIA-4) which is an acrylic polyol resin, 26.5 parts of “Vernok 980”,150 parts of methylethylketone, and 15.3 parts of triethylamine and,thus-obtained water dispersion of crosslinked particles has nonvolatilecomponents of 32.3% in thus-obtained water dispersion of crosslinkedparticles and a dispersion state was also excellent.

Subsequently, the water dispersion of crosslinked particles waspartially taken out, and tetrahydrofran was added in a 100 times amountand, as a result, it was muddy without transparently dissolving.Further, the water dispersion was maintained at 50° C. for 20 days, anda change was observed with a lapse of time and, as a result, any changewas not observed in stability of dispersibility.

Likewise, when ethyleneglycol monobutylether was added in amountcorresponding to 20% based on solid components, any change was notobserved in viscosity properties even after 20 days at 50° C. It is tobe noted that it has an average molecular weight ranging in 580-680between crosslinking points in the crosslinked particles, which is adesigned value, and which only slightly changes through reaction betweenglycidyl groups.

Still further, a solvent was added in an amount corresponding to 20%based on solid components and, as a result, a film-forming temperaturewas not more than room temperatures.

Example VI-5

The same procedures were followed as in the Example 1, except that therewere employed 205.8 parts of the vinyl-based copolymer (VIA-5) which isan acrylic polyol resin, 39.7 parts of “Vernok 980”, 150 parts ofmethylethylketone, and 10.8 parts of triethylamine and, as a result,nonvolatile components were 35.3% in thus-obtained water dispersion ofcrosslinked particles and a dispersion state was also excellent.

Subsequently, the water dispersion of crosslinked particles waspartially taken out, and tetrahydrofran was added in a 100 times amountand, as a result, it was muddy without transparently dissolving.Further, the water dispersion was maintained at 50° C. for 20 days, anda change was observed with a lapse of time and, as a result, any changewas not observed in stability of dispersibility.

Likewise, when ethyleneglycol monobutylether was added in an amountcorresponding to 20% based on solid components in the water dispersion,any change was not observed in viscosity properties even after 20 daysat 50° C. It is to be noted that it showed an average molecular weightof 630 between crosslinking points in the crosslinked particles, whichis a designed value.

Still further, a solvent was added in an amount corresponding to 20%based on solid components and, as a result, a film-forming temperaturewas not more than room temperatures.

Example VI-6

A 4-necked flask replaced with nitrogen was charged with 250 parts of“Unicef PT-200” [a polytetramethylene glycol having Mn=2,000manufactured by Nihon Yushi, Ltd.] and 55.5 parts by weight ofisophorone diisocyanate, and a reaction was conducted at 120° C. for 30minutes. 0.05 part of tin octoate was supplied, and the reaction wasfurther conducted for 60 minutes at the same temperature. After loweringthe temperature to 80° C., 182.5 parts of methylethylketone and 33.5parts of dimethylol propionic acid were supplied, and a reaction wasconducted at 80° C. for 6 hours to obtain a urethane prepolymer havingnonvolatile components of 65%, an acid value of 41.4, and an isocyanategroup content of 3.0%.

After that, there were sufficiently mixed 200 parts of the polymer, 51.6parts of “Vernok 980”, 100 parts of methylethylketone, and 5.0 parts oftriethylamine while sufficiently agitating, and 600 parts of distilledwater was added while continuing agitation and, subsequently, there wasalso added an aqueous solution in which 12 parts of diethylene triamineis dissolved in 100 parts of distilled water, and solvent and water werepartially distilled off at 60-70° C. while maintaining a system at areduced pressure to obtain a water dispersion of crosslinked particleshaving nonvolatile components of 31.0%.

Subsequently, 194 parts of thus-obtained water dispersion of crosslinkedparticles, 407 parts of distilled water, and 12 parts of toluene wereadded into a 4-necked flask replaced with nitrogen, followed byelevating a temperature to 80° C. After that, there were added dropwiseover 4 hours a solution in which there were mixed 4 parts of allylmethacrylate, 13 parts of methylmethacrylate, 13 parts ofbutylmethacrylate, and the ε-caprolactone-modified acrylic monomerobtained in the Example 4 and an aqueous solution in which there weremixed 0.15 part of ammonium persulphate is dissolved in 20 parts ofdistilled water, respectively, and a polymerization was conducted.

Also after that, agitation was continued for 2 hours at the sametemperature. Subsequently, solvent and water were partially distilledoff at a reduced pressure to obtain acryl/urethane composite crosslinkedparticles having nonvolatile components of 32.7%.

Subsequently, water dispersion of the crosslinked particles waspartially taken out, and a 100 times amount of tetrahydrofran was addedand, as a result, it was whitened without transparently dissolving.Further, a change with a lapse of time was observed while maintainingthe water dispersion at 50° C. for 20 days and, as a result, any changewas not observed in dispersion stability at all. Likewise, whenethyleneglycol monobutylether was added in amount corresponding to 20%based on solid components in the water dispersion, any change was notobserved in viscosity properties even after 20 days at 50° C. It is tobe noted that it showed an average molecular weight of 500 betweencrosslinking points in the crosslinked particles, which is a designedvalue.

Still further, a solvent was added in an amount corresponding to 20%based on solid components and, as a result, a film-forming temperaturewas not more than room temperatures.

Comparative Example VI-1

The same procedures were likewise followed as in the Example 1, exceptthat the vinyl-based copolymer (VIRA-1) was employed in place of thevinyl-based copolymer (VIA-1).

Comparative Example VI-2

The same procedures were likewise followed as in the Example 1, exceptthat the vinyl-based copolymer (VIRA-2) was employed in place of thevinyl-based copolymer (VIA-5) in the Example VI-5.

Comparative Example VI-3

The same procedures were likewise followed as in the Example 1, exceptthat the vinyl-based copolymer (VIRA-1) was employed in place of theε-caprolactone-modified acrylic monomer obtained in the Example 4 in theExample VI-6.

Comparative Examples VI-4 and VI-5

As a conventional type of method for forming a coating layer, there areemployed a commercially supplied baking type thermosetting coatingcomposed of an acrylic resin/melamine resin and a commercially suppliedordinary temperature-curing type coating composed of an acrylicresin/polyisocyanate resin, respectively, and both are a resincomposition for a top coating for cars.

Application Examples VI-1 and VI-6 and Comparative Application ExamplesVI-1 and VI-4

Subsequently, the respective crosslinked particles obtained in theExamples and Comparative Examples were employed solely or formulatedwith “MW12LF” [a melamine resin manufactured by Sanwa Chemical, Ltd.,nonvolatile components=75.6%] which is a cross-linking agent, followedby spray coating on a metal plate, a white base, or an electro-depositedcoating plate by a usual method, respectively, to allow to form acoating layer.

Subsequently, a variety of physical properties were evaluated inrelation to respective coating layers.

Further, respective evaluations were conducted according to methodsshown hereinafter.

[Boiling water resistance] Coated test plates were immersed in boilingwater for 60 minutes, and surface coating conditions were visuallyobserved and evaluated.

◯: Abnormal portions are not observed at all.

Δ: Softening or whitening are slightly observed.

x: Softening or whitening are remarkably observed.

[Staining resistance] Coated test plates were marked by a red or blackoil-soluble type felt pen. After having placed for 60 minutes, thosewere wiped by alcohols, and staining conditions were visually observedand evaluated.

◯: Marks are almost not remained.

Δ: Marks are slightly remained.

x: Marks are almost not removed.

[Impact resistance] Using a Dupon't style impact tester, there wasdropped a weight having 1 kg and radius of ½ inch in a striking pin, andimpact resistance is shown by a maximum height ((cm)) at which cracksare not caused in coated surface.

[Chipping resistance] Using a sand blasting tester (a productmanufactured by Suga Shikenki, Ltd.), a coated test plate was verticallyset in a sample holder of the tester. 50 g of No. 7 crushed stones weresprayed by air pressure of 4 kg/(cm)² from the tester, and crushedstones were struck at right angles against the plate. After that, thetest pieces were washed by water, and dried to evaluate and judge acondition of abrasion in the coating layer caused by chipping accordingto the following rules.

It is to be noted that the test pieces were placed in a thermostaticchamber cooled at −25° C. for 20 minutes, and chipping test wasconducted according to the above-described methods immediately afterhaving taken out.

: Peeling and blisters of coating layer are not observed at all.

◯: Peeling and blisters of coating layer are slightly observed.

x: Peeling and blisters of coating layer are remarkably observed.

[Adhesion] 11 pieces of lines crossed at right angles were lengthwiseand laterally made at an interval of 1 mm in a nearly center portion ofthe test pieces by a cutter knife until attaining to the plate itself,and 100 pieces of cross-hatches were made in 1 (cm)², and a cellophanetape was stuck on the surface, and it was visually evaluated by countingthe number of the cross-hatches remained after having been abruptlystripped.

◯: Peeling of coating layer is not observed at all.

Δ: Peeling of coating layer is slightly observed.

x: Peeling of coating layer is remarkably observed.

[Gloss] It was evaluated by a mirror surface reflection using 60-mirrorsurface photometer.

[Solvent resistance] Xylene or acetone was absorbed in a felt, followedby rubbing 200 times while loading the weight of 1 kg using a rubbingapparatus. It is shown by gloss retention ratio in a surface of acoating layer.

[Acid resistance] 10% sulphric acid aqueous solution was spotted on acoating surface, and it was evaluated at 10 grades by visually observingblisters and damages of a coating layer after maintaining at 60° C. for30 minutes.

[Alkali resistance] A coated plate was immersed in 5% KOH aqueoussolution at room temperatures for 100 hours, and it was visuallyevaluated by a level of damages.

[Hardness] It was evaluated by pencil hardness.

[Weatherability] A coated plate was placed in “Sunshine weather-O-meter”manufactured by Suga Shikenki, Ltd., a weatherability accelerating testwas conducted over 1,000 hours, and it is shown by gloss retentionratio.

[Pot life] It was measured according to JIS K5400 (1999)4.9.

From the Examples and Comparative Examples, it is evident that in thecase of employing a coating having a low proportion of -caprolactoneadducts containing 2 continuous chains as, for example, a top-coatingmaterial for cars, there can be obtained a coating layer which iswell-balanced among excellent workability, a hardness of a coatinglayer, a finishing outer appearance, weatherability, acid resistance,stain resistance, gloss, flexibility, and abrasion resistance.

Example VII Examples VII-1 and VII-2 Synthesis of an Acrylic Polyol(VII-A)

A reaction vessel equipped with an agitator, a thermometer, a refluxcondenser, tube for introducing nitrogen gas, and a dropping funnel wascharged with 30 parts of isobutyl acetate and 9 parts of xylene,followed by elevating a temperature to 105° C. while supplying nitrogengas. After that, a mixture described hereinafter was dropped from thedropping funnel over 4.5 hours to conduct a radical polymerization.After the completion of dropping of the mixture, a solution composed of5 parts of xylene and 0.5 part of 2,2′-azobisisobutyronitrile (AIBN) wasdropped over 1 hour at 110° C.

After the completion of dropping, aging was conducted at 115 for 1.5hour, followed by cooling to obtain an acrylic polyol resin solution(solid content of 60%) described below.

Acrylic polyol resin (VIIA 1): 25.1 parts of styrene, 5.3 parts of MMA,32.3 parts of butylacrylate, 4.9 parts of glycidyl methacrylate, 31.6parts of the above-described FM0.50, 18 parts of xylene, 1.7 part ofAIBN. In the acrylic polyol resin, a number average molecular weight was9,700, and OHV was 74 mg-KOH/g.

Acrylic polyol resin (VIIA 2): The same polymerization was conducted asin the acrylic polyol resin (VIIA 1) except that FM0.75 was employed inplace of the FM0.50, In the acrylic polyol resin, a number averagemolecular weight was 9,800, and OHV was 73 mg-KOH/g.

Acrylic polyol resin (VIIA3): (composition) 28.1 parts of styrene, 5.3parts of MMA, 32.3 parts of butyl acrylate, 2.0 parts of methacrylicacid, 31.6 parts of FM1.0 (an adduct in which caprolactone is added tohydroxyethylmethacrylate in 1.0 mol on an average manufactured by DaicelKagaku kogyo, Ltd.), 18 parts of xylene, 1.7 part of AIBN. In acopolymer obtained, a number average molecular weight was 9,500, and OHVwas 74 mg-KOH/g.

Acrylic polyol resin (VIIA4): (composition) 25.1 parts of styrene, 5.3parts of MMA, 32.3 parts of butyl acrylate, 4.9 parts of glycidylmethacrylate, 31.6 parts of FM1.0, 18 parts of xylene, 1.7 part of AIBN.In a copolymer obtained, a number average molecular weight was 9,700,and OHV was 74 mg-KOH/g.

Acrylic polyol resin (VIIA 5): (composition) 5.0 parts ofdimethylaminomethacrylate, 28.5 parts of MMA, 32.3 parts of butylacrylate, 2.0 parts of methacrylic acid, 4.9 parts of glycidylmethacrylate, 31.6 parts of FM1.0, 18 parts of xylene, 1.7 part of AIBN.In a copolymer obtained, a number average molecular weight was 9,800,and OHV was 74 mg-KOH/g.

Synthesis of a Copolymer (VII-B) Containing an Alkoxysilyl Group

A reaction vessel equipped with an agitator, a thermometer, a refluxcondenser, tube for introducing nitrogen gas, and a dropping funnel wascharged with 45.7 parts of xylene, followed by elevating a temperatureto 108° C. while supplying nitrogen gas.

After that, a mixture described hereinafter was dropped from thedropping funnel over 5 hours to conduct a radical polymerization. Afterthe completion of dropping of the mixture, 0.5 part of AIBN and 5 partsof xylene were dropped over 1 hour.

After the completion of dropping, aging was conducted at 115° C. for 1.5hour, followed by cooling to obtain a solution of a copolymer containingan alkoxysilyl group (solid content of 60%) described below.

Copolymer (VII B1) containing an alkoxysilyl group: (composition) 12.7parts of styrene, 44.9 parts of MMA, 6.8 parts of stearyl methacrylate,30 parts of γ-methacryloxypropyl trimethoxysilane, 4.9 parts of glycidylmethacrylate, 18.4 parts of xylene, 4.5 part of2,2′-azobisisobutyronitrile (AIBN). In a copolymer obtained, a numberaverage molecular weight was 6000.

Copolymer (VII B2) containing an alkoxysilyl group: (composition) 12.7parts of styrene, 44.9 parts of MMA, 6.8 parts of stearyl methacrylate,30 parts of γ-methacryloxypropyl trimethoxysilane, 4.9 parts of maleicanhydride, 18.4 parts of xylene, 4.5 part of 2,2′-azobisisobutyronitrile(AIBN). In a copolymer obtained, a number average molecular weight was6000.

[Preparation of a Coating]

A coating having composition shown in Table VII-7 was prepared using 36parts of any one of the above-described acrylic polyol resins VIIA 1 toVII A5 and 24 parts of any one of the above-described copolymers VII B1to VII B2 containing an alkoxysilyl group, respectively.

In Table VII-7, A-1120 and A-187 are a product manufactured by UCC, Co.;Tinuvin 900 is an ultraviolet ray absorbent manufactured by Ciba Geigy,AG., Tinuvin 144 is a photostabilizer manufactured by Ciba Geigy, AG.;PS399.7 is a polydimethyl siloxane having silanol group at terminalsmanufactured by Chisso, Co.; Solvesso #100 is an aromatic solvent havinga high boiling point.

[Coating and Evaluation]

A coated plate for a test piece was prepared by coating an epoxyamide-based cationic electro-deposition primer and a middle coatingsurfacer for cars onto a mild steel plate degreased and treated byphosphatization (provided, a glass plate in an abrasion test). On theplate, there was coated a base coat (an acrylmelamine resin coating) atop coat clear coating having composition shown in Table No. 7 bywet-on-wet, followed by setting for 20 minutes and baking at 140° C. for30 minutes.

Thickness of a dried coating layer was approximately 15 μm in base coatand approximately 30 μm in the topcoat clear coating. Coated articlesobtained were evaluated as described below, and results are shown in theTable VI-7.

As a result, in the coatings composed of the composition of the presentinvention, an abrasion resistance is improved without loss of otherproperties.

Outer appearance: It was visually evaluated overall by gloss and a buildfeeling. ◯ is excellent, Δ is usual, and x is worse.

Adhesion: Cross-hatched (2 mm×2 mm) test was conducted using acellophane tape and, in evaluation, 25/25 is 10 scores, 0/25 is 0 score.

Hardness: It was measured according to JIS K5400.

Acid resistance: 5-6 droplets of 38% H₂SO₄ were spotted on test pieces,and the test pieces were placed at room temperature for 24 hours. Afterhaving wiped, marks were checked. ◯: It is not abnormal, Δ: Marks areremained and sheariness is slightly caused, and x: sheariness iscompletely caused.

Staining resistance: An engine oil after approximately 5,000 km-runningwas coated on a test piece, and the test piece was placed in conditionsof 50° C. and 98% RH for 24 hours. After having taken out and wiped, andthe test piece was compared to an untested piece.

◯: no change Δ: slight color change, and x: distinct change

Abrasion resistance: Using a Haze meter (a turbidimeter) NDH-300Amanufactured by Nihon Densyoku Kogyo, there was measured a Haze value(Haze value before rubbing) in a glass-made base plate having a coatinglayer, and there was measured a Haze value (Haze value after rubbing)after having abraded at 5 cycles using stainless steel wool under aloading of 200 g, and difference was calculated. Measured value is anaverage value of 2 times.

Weatherability: Using Youbucon manufactured by Atlas Co., an ultravioletray was irradiated at 70° C. for 8 hours, and an accelerating test wasconducted at a cycle of water coagulation (darkness) at 50° C. for 4hours, in which a test is conducted for 7000 hour and 8000 hours, andretention ratio of gloss is evaluated.

Contact angle: A contact angle meter CA-P type manufactured by KyowaKaimen Kagaku, Ltd. was employed to measure a contact angle (degree)against water.

Rubbing property: MEK (methylethyl ketone) was absorbed in degreasedcotton, and respective test pieces were rubbed 300 times at sameconditions, and a condition was observed. Evaluation was conducted thatis no change, and ◯ is a condition having a small amount of scratches inthe surface.

Transition of gel fraction: Coatings were coated on a fluorized resinfilm, respectively, and a film having a thickness of 30 μm was preparedby baking at 140° C. for 30 minutes. There were measured a gel fraction(an acetone-extracting method) of a film obtained and a gel fractionafter having immersed in warmed water of 60° C. for 1 month.

In the Table shown below, VII is omitted

Example Comparative Example 1 2 1 2 3 4 [Composition] Component A A-1A-2 A-3 A-5 A-4 A-4 Component B B-2 B-2 B-2 B-1 B-2 B-2 Dioctyltinmaleate 0.72 0.72 0.72 0.72 0.72 0.72 Reaction product 0.72 0.72 0.720.72 0.72 0.72 of A-1120 with A-187 Tinuvin 900 0.36 0.36 0.36 0.36 0.360.36 Tinuvin 144 0.36 0.36 0.36 0.36 0.36 0.36 PS399.7 1.8 — — — — 1.8Solvesso #100 34.24 34.24 34.24 34.24 34.24 34.24 Methanol 1.8 1.8 1.81.8 1.8 1.8 Ortho methyl acetate 1.8 1.8 1.8 1.8 1.8 1.8 [Coating] Outerappearance ◯ ◯ ◯ ◯ ◯ ◯ Adhesion 10 10 10 10 10 10 Hardness 2H 2H 2H 2H2H 2H Acid resistance ◯ ◯ ◯ ◯ ◯ ◯ Staining resistance ◯ ◯ ◯ ◯ ◯ ◯Abrasion resistance (Haze value) before rubbing 0.16 0.16 0.37 0.31 0.340.39 after rubbing 2.76 2.81 3.75 3.28 3.45 3.95 Difference between 2.602.65 3.38 2.97 3.11 3.56 before and after Weatherability 700 hours 97 9898 99 97 98 2800 hours 93 92 90 90 93 92 Contact angle against water 8090 79 79 80 90 MEK rubbing property ⊚ ⊚ ◯ ◯ ◯ ◯ (300 times) Gel fractionbefore immersion 95.2 95.0 95.3 95.8 95.2 95.0 after immersion 92.2 92.391.2 91.0 92.2 92.3

Example VIII Example VIII-1

A 500-ml glass-made flask equipped with an agitating device, athermometer, and a water cooling condenser was charged with 88.4 g (0.41mol) of the lactone-modified 2-hydroxyethylmethacrylate composition(a-1) obtained in the Example 1, 40.2 g (0.41 mol) of maleic anhydride,0.39 g of N-methylimidazole, and 0.09 g of hydroquinone monomethylether.

Subsequently, the flask was heated while agitating and streaming airinto a gas phase portion, and it was maintained at liquid temperature at90° C. for 8 hours and, an esterification reaction was further conductedat 100° C. for 3 hours.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappeared maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c-1) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 180 mgKOH/g that the product is a carboxylic group-contained acrylate monomermodified by a small amount of lactones in which one molecule of maleicanhydride is added to the lactone-modified 2-hydroxyethylmethacrylatecomposition (a-1).

Example VIII-2

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 177 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-2) obtained in the Example 2and 80.4 g (0.82 mol) of maleic anhydride were employed in place of 88.4g (0.41 mol) of the lactone-modified 2-hydroxyethylmethacrylatecomposition (a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappeared maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c-2) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 180 mgKOH/g that the product is a carboxylic group-contained acrylate monomermodified by a small amount of lactones in which one molecule of maleicanhydride is added to the lactone-modified 2-hydroxyethylmethacrylatecomposition (a-2).

Example VIII-3

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 153 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-3) obtained in the Example 3and maleic anhydride (0.82 mol) were employed in place of 88.4 g (0.41mol) of the lactone-modified 2-hydroxyethylmethacrylate composition(a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappeared maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c-3) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 197 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-3).

Example VIII-4

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 161 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-4) obtained in the Example 4and maleic anhydride (0.82 mol) were employed in place of 88.4 g (0.41mol) of the lactone-modified 2-hydroxyethylmethacrylate composition(a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappeared maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c-4) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 191 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-4).

Comparative Example VIII-1

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 200 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a′-1) obtained in theComparative Example 1 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c′-1) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 164 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Comparative Example VIII-2

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 200 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a′-2) obtained in theComparative Example 2 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c′-2) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 164 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Comparative Example VIII-3

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 286 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a′-3) obtained in theComparative Example 3 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c′-3) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 123 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Comparative Example VIII-4

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 387 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a′-4) obtained in theComparative Example 4 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappeared maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c′-4) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 98.4 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Comparative Example VIII-5

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 481 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a′-5) obtained in theComparative Example 5 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c′-5) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 82.0 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Example VIII-5

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 60.7 g (0.41 mol) of phthalic anhydride was employedin place of maleic anhydride in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear phthalic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c-5) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 154 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof phthalic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Example VIII-6

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 78.7 g (0.41 mol) of trimellitic anhydride wasemployed in place of maleic anhydride in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear trimellitic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c-6) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 275 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones in which one moleculeof trimellitic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Example VIII-7

The quite same esterification reaction was conducted as in the ExampleVIII-1, except that 89.4 g (0.41 mol) of pyromellitic anhydride wasemployed in place of maleic anhydride in the Example VIII-1.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappeared pyromellitic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (c-7) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 129 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition modified by a small amount of lactones having carboxylicgroup in which one molecule of pyromellitic anhydride is added to thelactone-modified 2-hydroxyethylmethacrylate composition (a-1).

Example IX Synthesis of Carboxylic Group-Contained Acrylate MonomerCompositions (a′-1 to a′-7, a″-1 to a″-5) Modified by a Small Amount ofLactones Reference Example IX-5

A 500-ml glass-made flask equipped with an agitating device, athermometer, and a water cooling condenser was charged with 88.4 g (aterminal hydroxyl group of 0.41 mol, hereinafter, the same) of thelactone-modified 2-hydroxyethylmethacrylate composition (a-1) obtainedin the Example 1, 40.2 g (0.41 mol) of maleic anhydride, 0.39 g ofN-methylimidazole, and 0.09 g of hydroquinone monomethylether.

Subsequently, the flask was heated while agitating and streaming airinto a gas phase portion, and it was maintained at liquid temperature at90° C. for 8 hours and, an esterification reaction was further conductedat 100° C. for 3 hours.

Reaction product was a light yellowish liquid, and it was confirmed thatthere disappear maleic anhydride and the lactone-modified2-hydroxyethylmethacrylate which are a starting raw material and thereis newly produced a carboxylic group-contained acrylate monomer (a′-1)modified by a small amount of lactones by a GPC analysis. As a result ofthe analysis, it was confirmed from an acid value of 180 mg KOH/g thatthe product is a carboxylic group-contained acrylate monomer composition(a′-1) modified by a small amount of lactones in which one molecule ofmaleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Reference Example IX-6

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 177 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-2) obtained in the Example 2and maleic anhydride (0.82 mol) were employed in place of 88.4 g (0.41mol) of the lactone-modified 2-hydroxyethylmethacrylate composition(a-1) in the Reference Example IX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-2) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 180 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-2) modified by a small amount of lactones in which onemolecule of maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-2).

Reference Example IX-7

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 153 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-3) obtained in the Example 3and maleic anhydride (0.82 mol) were employed in place of 88.4 g (0.41mol) of the lactone-modified 2-hydroxyethylmethacrylate composition(a-1) in the Reference Example IX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a raw material andthere is newly produced a carboxylic group-contained acrylate monomer(a′-3) modified by a small amount of lactones. As a result of theanalysis, it was confirmed from an acid value of 197 mg KOH/g that theproduct is a carboxylic group-contained acrylate monomer composition(a′-3) modified by a small amount of lactones in which one molecule ofmaleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-3).

Reference Example IX-8

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 161 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-4) obtained in the Example 4and maleic anhydride (0.82 mol) were employed in place of 88.4 g (0.41mol) of the lactone-modified 2-hydroxyethylmethacrylate composition(a-1) in the Reference Example IX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-4) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 191 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-4) modified by a small amount of lactones in which onemolecule of maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-4).

Comparative Reference Example IX-6

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 200 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1′) obtained in theComparative Example 1 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Reference ExampleIX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-1′) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 164 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-1′) modified by a small amount of lactones in which onemolecule of maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1′).

Comparative Reference Example IX-7

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 200 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-2′) obtained in theComparative Example 2 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Reference ExampleIX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-2′) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 164 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-2′) modified by a small amount of lactones in which onemolecule of maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-2′).

Comparative Reference Example IX-8

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 286 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-3′) obtained in theComparative Example 3 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Reference ExampleIX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-3′) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 123 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-3′) modified by a small amount of lactones in which onemolecule of maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-3′).

Comparative Reference Example IX-9

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 387 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-4′) obtained in theComparative Example 4 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Reference ExampleIX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-4′) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 98.4 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-4′) modified by a small amount of lactones in which onemolecule of maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-4′).

Comparative Reference Example IX-10

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 481 g (0.82 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-5′) obtained in theComparative Example 5 and maleic anhydride (0.82 mol) were employed inplace of 88.4 g (0.41 mol) of the lactone-modified2-hydroxyethylmethacrylate composition (a-1) in the Reference ExampleIX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear maleic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-5′) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 82.0 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-5′) modified by a small amount of lactones in which onemolecule of maleic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-5′).

Reference IX-9

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 60.7 g (0.41 mol) of phthalic anhydride wasemployed in place of maleic anhydride in the Reference Example IX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappeared phthalic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-5) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 154 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-5) modified by a small amount of lactones in which onemolecule of phthalic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Reference IX-10

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 78.7 g (0.41 mol) of trimellitic anhydride wasemployed in place of maleic anhydride in the Reference Example VIII-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear trimellitic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-6) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 275 mgKOH/g that the product is a carboxylic group-contained acrylate monomercomposition (a′-6) modified by a small amount of lactones in which onemolecule of trimellitic anhydride is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

Reference IX-11

The quite same esterification reaction was conducted as in the ReferenceExample IX-5, except that 89.4 g (0.41 mol) of pyromellitic anhydridewas employed in place of maleic anhydride in the Reference Example IX-5.

Reaction product was a light yellowish liquid, and it was confirmed by aGPC analysis that there disappear pyromellitic anhydride and thelactone-modified 2-hydroxyethylmethacrylate which are a starting rawmaterial and there is newly produced a carboxylic group-containedacrylate monomer (a′-7) modified by a small amount of lactones. As aresult of the analysis, it was confirmed from an acid value of 129 mgKOH/g that the product is a tricarboxylic group-contained acrylatecomposition (a′-7) modified by a small amount of lactones in which onemolecule of pyromellitic acid is added to the lactone-modified2-hydroxyethylmethacrylate composition (a-1).

[Synthesis of an Acrylic Polycarboxylic Acid Resin (A′-1 to A′-6, A′-1′to A′-8)] Synthesis Example IX-1 Synthesis of a Half-Esterified AcrylicPolycarboxylic Acid Resin (A′-1)

A 3-liter reaction vessel equipped with a thermometer, an agitator, areflux condenser, a tube for introducing nitrogen, and a dropping funnelwas charged with 200 parts of xylene, 100 parts of Solvesso 100, and 100parts of propyleneglycol monomethylether acetate followed by elevating atemperature to 125° C. Into the vessel, there were added dropwise amonomer solution composed of 100 parts of the carboxylic group-containedacrylate composition (a′-1) modified by a small amount of lactonesobtained in the Reference Example IX-5, 200 parts of styrene, 580 partsof cyclohexyl acrylate, 220 parts of maleic anhydride, and 400 parts ofpropyleneglycol monomethylether acetate and an initiator solutioncomposed of 100 parts of t-butylperoxy-2-ethylhexanoate and 100 parts ofxylene from the dropping funnel over 3 hours. After the completion ofdropwise addition, the vessel was maintained at 130° C. over 30 minutes,followed by adding dropwise an initiator solution composed of 10 partsof t-butylperoxy-2-ethylhexanoate and 50 parts of xylene over 30minutes. After the completion of dropwise addition, reaction was furthercontinued at 130° C. over 1 hour to obtain a resin varnish (nonvolatilecomponents of 50%) containing an acrylic polyacid anhydride having anumber average molecular weight of 3,800.

86 parts of methanol was added to 2060 parts of the varnish, followed byallowing to react at 70° C. for 23 hours to obtain a half-esterifiedvarnish having an acid value of 126 mg-KOH/g-solid.

It is to be noted that it was confirmed that infrared absorption spectrawere measured in the resin obtained and there disappears an absorption(1785 (cm)⁻¹) by an acid anhydride.

Synthesis Example IX-2 Synthesis of an Acrylic Polycarboxylic Acid Resin(A′-2)

The same vessel as in the Synthesis Example IX-1 was charged with 700parts of xylene and 500 parts of Solvesso 100, followed by elevating atemperature to 130° C. Into the vessel, there were added dropwise amonomer solution composed of 380 parts of the acrylate composition(a′-1) modified by a small amount of lactones having carboxylic groupobtained in the Reference Example IX-5, 300 parts of styrene, 350 partsof 2-ethylhexyl acrylate, 150 parts of isobutylmethacrylate, and 200parts of acrylic acid and an initiator solution composed of 150 parts oft-butylperoxy-2-ethylhexanoate and 300 parts of xylene from the droppingfunnel over 3 hours. After the completion of dropwise addition, thevessel was maintained at 130° C. over 30 minutes, followed by addingdropwise an initiator solution composed of 20 parts oft-butylperoxy-2-ethylhexanoate and 20 parts of xylene over 30 minutes.After the completion of dropwise addition, reaction was furthercontinued at 130° C. over 1 hour, followed by removing 1100 parts ofsolvents to obtain a resin varnish (nonvolatile components of 70%)having a number average molecular weight of 1,800 and an acid value of156 mgKOH/g solid.

Synthesis Example IX-3

The same vessel as in the Synthesis Example IX-1 was charged with 700parts of xylene and 350 parts of Solvesso 100, followed by elevating atemperature to 130° C. Into the vessel, there were added dropwise amonomer solution composed of 240 parts of the carboxylic group-containedacrylate composition (a′-1) modified by a amall amount of lactonesobtained in the Reference Example 5, 300 parts of styrene, 258 parts of2-ethylhexyl acrylate, 151 parts of isobutylmethacrylate, 51 parts ofacrylic acid, 240 parts of maleic anhydride, and 300 parts ofpropyleneglycol monomethylether acetate and an initiator solutioncomposed of 150 parts of t-butylperoxy-2-ethylhexanoate and 150 parts ofxylene from the dropping funnel over 3 hours. After the completion ofdropwise addition, the vessel was maintained at 125° C. over 30 minutes,followed by adding dropwise an initiator solution composed of 20 partsof t-butylperoxy-2-ethylhexanoate and 20 parts of xylene over 30minutes. After the completion of dropwise addition, reaction was furthercontinued at 125° C. over 1 hour, followed by removing 1000 parts ofsolvents to obtain a varnish containing a resin (nonvolatile componentsof 65%) having a number average molecular weight of 2,000.

125 parts of methanol was added to 1590 parts of the varnish, followedby allowing to react at 70° C. for 23 hours to obtain a varnishcontaining a half-esterified acrylic polycarboxylic acid resin (A′-3)having an acid value of 126 mg KOH/g-solid. It is to be noted that itwas confirmed that infrared absorption spectra were measured in theresin obtained and an absorption by an acid anhydride disappears.

Synthesis Example IX-4

The quite same procedures were followed as in the Synthesis ExampleIX-1, except that the acrylate composition (a′-1) modified by a smallamount of lactones having carboxylic group in the Synthesis Example IX-1was replaced with 100 parts of the acrylate composition (a′-2) modifiedby a small amount of lactones having carboxylic group obtained in theReference Example IX-6 to obtain a varnish containing a half-esterifiedresin (A′-4) having a number average molecular weight of 1,800 and anacid value of 158 mg-KOH/g-solid. It is to be noted that it wasconfirmed that infrared absorption spectra were measured in the resinobtained and there disappears an absorption by an acid anhydride.

Synthesis Example IX-5 Synthesis of an Acrylic Polycarboxylic Acid(A′-5)

The quite same procedures were followed as in the Synthesis ExampleIX-2, except that the acrylate composition (a′-1) modified by a smallamount of lactones having carboxylic group in the Synthesis Example IX-2was replaced with 345 parts of the acrylate composition (a′-7) modifiedby a small amount of lactones having carboxylic group obtained in theReference Example IX-7 to obtain a varnish containing a resin having anumber average molecular weight of 3,800 and an acid value of 126mg-KOH/g-solid. It is to be noted that it was confirmed that infraredabsorption spectra were measured in the resin obtained and theredisappears an absorption by an acid anhydride.

Synthesis Example IX-6

The quite same procedures were followed as in the Synthesis ExampleIX-3, except that the acrylate composition (a′-1) modified by a smallamount of lactones having carboxylic group in the Synthesis Example IX-3was replaced with 225 parts of the acrylate composition (a′-8) modifiedby a small amount of lactones having carboxylic group obtained in theReference Example IX-8 to obtain a varnish containing a resin (A′-6)having a number average molecular weight of 2,000 and an acid value of126 mg-KOH/g-solid. It is to be noted that it was confirmed thatinfrared absorption spectra were measured in the resin obtained andthere disappears an absorption (1785 (cm)⁻¹) by an acid anhydride.

Comparative Synthesis Example IX-1 Synthesis of an AcrylicPolycarboxylic Acid (A′-1′)

The quite same procedures were followed as in the Synthesis ExampleIX-2, except that the acrylate composition modified by small amount oflactones having carboxylic group in the Synthesis Example IX-2 wasreplaced with 414 parts of the acrylate monomer (a′-1′) modified by asmall amount of lactones having carboxylic group obtained in theComparative Reference Example IX-1 to obtain a varnish containing aresin having a number average molecular weight of 3,800 and an acidvalue of 126 mg-KOH/g-solid. It is to be noted that it was confirmedthat infrared absorption spectra were measured in the resin obtained andthere disappears an absorption (1785 (cm)⁻¹) by an acid anhydride.

Comparative Synthesis Example IX-2 Synthesis of an AcrylicPolycarboxylic Acid (A′-2′)

The quite same procedures were followed as in the Synthesis ExampleIX-2, except that the acrylate composition modified by a small amount oflactones having carboxylic group in the Synthesis Example IX-2 wasreplaced with 414 parts of the acrylate composition (a′-2′) modified bya small amount of lactones having carboxylic group obtained in theComparative Reference Example IX-2 to obtain a varnish containing aresin having a number average molecular weight of 3,800 and an acidvalue of 126 mg-KOH/g-solid.

It is to be noted that it was confirmed that infrared absorption spectrawere measured in the resin obtained and there disappears an absorption(1785 (cm)⁻¹) by an acid anhydride.

Comparative Synthesis Example IX-3 Synthesis of an AcrylicPolycarboxylic Acid (A′-3′)

The quite same procedures were followed as in the Synthesis Example 2,except that the carboxylic group-contained acrylate composition modifiedby a small amount of lactones in the Synthesis Example IX-2 was replacedwith 550 parts of the carboxylic group-contained acrylate composition(a′-3′) modified by a small amount of lactones obtained in the ReferenceComparative Example IX-3 to obtain a varnish containing an acrylicpolycarboxylic acid resin (A′-3′) having a number average molecularweight of 3,800 and an acid value of 126 mg-KOH/g-solid. It is to benoted that it was confirmed that infrared absorption spectra weremeasured in the resin obtained and there disappears an absorption (1785(cm)⁻¹) by an acid anhydride.

Comparative Synthesis Example IX-4 Synthesis of an AcrylicPolycarboxylic Acid (A′-4′)

The quite same procedures were followed as in the Synthesis ExampleIX-2, except that the carboxylic group-contained acrylate compositionmodified by a small amount of lactones in the Synthesis Example IX-2 wasreplaced with 690 parts of the carboxylic group-contained acrylatecomposition (a′-4′) modified by small amount of lactones obtained in theReference Comparative Example IX-4 to obtain a varnish containing anacrylic polycarboxylic acid resin (A′-4′) having a number averagemolecular weight of 3,800 and an acid value of 126 mg-KOH/g-solid. It isto be noted that it was confirmed that infrared absorption spectra weremeasured in the resin and there disappears an absorption (1785 (cm)⁻¹)by an acid anhydride.

Comparative Synthesis Example IX-5 Synthesis of an AcrylicPolycarboxylic Acid (A′-5′)

The quite same procedures as in the Synthesis Example IX-2 were followedexcept that the carboxylic group-contained acrylate composition modifiedby a small amount of lactones in the Synthesis Example IX-2 was replacedwith 828 parts of the carboxylic group-contained acrylate composition(a′-5′) modified by a small amount of lactones obtained in the ReferenceComparative Example IX-5 to obtain a varnish containing an acrylicpolycarboxylic acid resin (A′-5′) having a number average molecularweight of 3,800 and an acid value of 126 mg KOH/g-solid. It is to benoted that it was confirmed that infrared absorption spectra weremeasured in the resin and there disappears an absorption (1785 (cm)⁻¹)by an acid anhydride.

Comparative Synthesis Example IX-6 Synthesis of a Half-EsterifiedAcrylic Polycarboxylic Acid (A′-6′)

The quite same procedures were followed as in the Synthesis ExampleIX-1, except that the carboxylic group-contained acrylate composition(a′-1) modified by a small amount of lactones in the Synthesis ExampleIX-1 was not added to obtain a varnish containing a half-esterifiedacrylic polycarboxylic acid resin (A′-6′) having a number averagemolecular weight of 1,800 and an acid value of 158 mg-KOH/g-solid. It isto be noted that it was confirmed that infrared absorption spectra weremeasured in the resin and there disappears an absorption (1785 (cm)⁻¹)by an acid anhydride.

Comparative Synthesis Example IX-7 Synthesis of an AcrylicPolycarboxylic Acid (A′-7′)

The quite same procedures were followed as in the Synthesis ExampleIX-2, except that the carboxylic group-contained acrylate composition(a′-1) modified by a small amount of lactones in the Synthesis ExampleIX-2 was not added to obtain a varnish containing an acrylicpolycarboxylic acid resin (A′-7′) having a number average molecularweight of 3,800 and an acid value of 126 mg KOH/g-solid. It is to benoted that it was confirmed that infrared absorption spectra weremeasured in the resin and there disappears an absorption (1785 (cm)⁻¹)by an acid anhydride.

Comparative Synthesis Example IX-8 Synthesis of a Half-EsterifiedAcrylic Polycarboxylic Acid (A′-8′)

The quite same procedures were followed as in the Synthesis Example IX-3except that the carboxylic group-contained acrylate composition modifiedby a small amount of lactones in the Synthesis Example IX-3 was notadded to obtain a varnish containing a half-esterified acrylicpolycarboxylic acid resin (A′-8′) having a number average molecularweight of 2,000 and an acid value of 125 mg-KOH/g-solid. It is to benoted that it was confirmed that infrared absorption spectra weremeasured in the resin and there disappears an absorption (1785 (cm)⁻¹)by an acid anhydride.

Synthesis of a Blocked Carboxylic Group-Contained Acrylic PolycarboxylicAcid (bA′-1 to bA′-2) Synthesis Example IX-7

A four-necked flask equipped with an agitating device, a thermometer, atube for introducing an inert gas, a dropping funnel, and a coolingdevice was charged with 412 g (2 mol) of the acrylic polycarboxylic acidresin (A′-1) obtained in the Synthesis Example 1, followed by adding1000 g of tetrahydrofran, 1 mol of ethylvinyl ether (a blocking agent),and 0.2 part of 35% sulphuric acid at 35° C. and allowing to react for24 hours at the temperature.

After the completion of reaction, a product was moved to a separatingfunnel, followed by alkali-washing using 100 g of 10% sodium bicarbonateand 100 g of a saturated aqueous salt. After having placed, a waterlayer was separated and removed. This operations were repeated 20 times,and washing by a saturated aqueous salt was conducted three times byadding sodium sulphate to an organic layer at room temperatures, andtertahydrofran was removed at a reduced pressure to obtain an acrylicpolycarboxylic acid (bA′-1) in which carboxylic groups are blocked byethylvinyl ether.

Synthesis Example IX-8

The same flask as in the Synthesis Example IX-7 was charged with 2 molof the acrylic polycarboxylic acid resin (A′-2) obtained in theSynthesis Example 2, followed by cooling at not more than 10° C. by icewater and adding 300 g of tetrahydrofran and 111 g of triethylamine. Asolution containing 1 mol of trimethylsilyl chloride (a blocking agent)dissolved in 100 g of tetrahydrofran was added dropwise into the flaskover 30 minutes and, an ice water bath was removed at a period of 1 hourafter the completion of dropwise addition, and a reaction was furthercontinued for 10 hours. Subsequently, washing was conducted three timeswith 100 parts of ice water, and tetrahydrofran was removed at reducedpressures to obtain an acrylic polycarboxylic acid (bA′-2) in whichcarboxylic groups are blocked by trimethylsilyl chloride.

Synthesis Example IX-9

A 2-liter reaction vessel equipped with a thermometer, an agitator, acooling device, a tube for introducing nitrogen, and a dropping funnelwas charged with 300 parts of xylene and 50 parts of propyleneglycolmonomethyletheracetate, followed by elevating a temperature to 125° C.

Into the reaction vessel, there were added dropwise over 3 hours amonomer solution composed of 320 parts of glycidyl methacrylate, 167parts of styrene, 100 parts of 2-ethylhexyl acrylate, and 413 parts ofFM0.75 obtained in the Reference Example IX-2 and an initiator solutioncomposed of 120 parts of t-butylperoxy 2-ethylhexanoate and 150 parts ofxylene.

After the completion of dropwise addition, the reaction vessel wasmaintained at 125° C. over 30 minutes, followed by adding dropwise aninitiator solution composed of 10 parts of t-butylperoxy2-ethylhexanoate and 200 parts of xylene over 30 minutes.

After the completion of dropwise addition, a reaction was furthercontinued at 125° C. for 1 hour to obtain a varnish (nonvolatilecomponents of 60%) containing a polyepoxide (IXB-1) having a numberaverage molecular weight of 3500, an epoxy equivalent of 450, and ahydroxyl value of 95 mgKOH/g solid.

Example IX-1

(Preparation of Crosslinked Resin Particles)

A reaction vessel equipped with an agitating and heating device, athermometer, a tube for introducing nitrogen, a reflux condenser, and adecanter was charged with 213 parts of bishydroxyethyl taurine, 208parts of neopentylglycol, 296 parts of phthalic anhydride, 376 parts ofazelaic acid, and 30 parts of xylene, followed by elevating atemperature. Water produced in a reaction was removed by azeotropicdistillation together with xylene. Temperature in reaction was elevatedto 210° C. over approximately 3 hours from initiation of reflux, and thereaction was continued while agitating and dehydrating until an acidvalue based on a carboxylic acid attains to 135 mgKOH/g solid. Afterhaving cooled the liquid temperature to 140° C., there was addeddropwise 500 parts of “Kardula E10” (glycidyl versate manufactured byShell, Co.) over 30 minutes, followed by continuing agitation for 2hours to complete the reaction. There was obtained a polyester resinhaving amphoteric ion groups which has an acid value of 55 mgKOH/gsolid, a hydroxyl value of 91 mgKOH/g solid, and a number averagemolecular weight of 1250 in solid components.

There was prepared a monomer suspension by vigorously agitating 10 partsof the polyester resin having amphoteric ion groups, 140 parts ofdeionized water, 1 part of dimethylethanol amine, 50 parts of styrene,and 50 parts of ethyleneglycol dimethacrylate in a stainless steel-madebeaker. Further, there was prepared an initiator aqueous solution bymixing 0.5 part of azobiscyano valeric acid, 40 parts of deionizedwater, and 0.32 part of dimethylethanol amine.

A reaction vessel equipped with an agitating and heating device, athermometer, a tube for introducing nitrogen, and a reflux condenser wascharged with 5 parts of the polyester resin having amphoteric iongroups, 280 parts of deionized water, and 0.5 part of dimethylethanolamine, followed by elevating a temperature 80° C. Into the reactionvessel, 251 parts of the monomer suspension and 40.82 parts of theinitiator aqueous solution were simultaneously added dropwise over 60minutes, and a reaction was further continued for 60 minutes, followedby terminating the reaction. There was obtained an emulsion ofcrosslinked resin particles having particle diameter of 55 nm which wasmeasured by a dynamic light scattering method.

Into the emulsion, xylene was added, and water was removed by azeotropicdistillation at a reduced pressure. There was obtained a xylene solutionof crosslinked resin particles having solid content of 20% by weight byreplacing a medium with xylene.

(Preparation of a Clear Coating Composition)

There were formulated the acrylic polycarboxylic acid resin (A′-1)obtained in the Synthesis Example X-1, a polyepoxide (IXB-1) obtained inthe Synthesis Example X-9, “Sumilizer BHT” (IXC-1) and “Sumilizer TPP-R”(IXC-2) which are manufactured by Sumitomo Kagaku, Co., and there werefurther added 0.5 part of tetrabutyl ammonium bromide which is a curingcatalyst (IXF-1), 1 part of dibutyltin bis(butylmaleate) which is acuring catalyst (IXG-1), 2 parts of “Tinuvin 900” which is anultraviolet ray absorbent manufactured by Ciba Geigy, AG., 1 part of“Sanol LS-440” which is a photostabilizer manufactured by Sankyo, Co.,and 0.1 part of “Modaflow” which is a surface controller manufactured byMonsanto Co. while agitating in Disper to prepare a curable resincomposition. In the resin composition obtained, there was further added10 parts of a xylene solution of the crosslinked resin particlesprepared as described hereinabove, and viscosity was adjusted to 30seconds by Ford Cup No. 4 using a solvent composed of butylacetate/xylene=1/1 to obtain a clear coating composition.

Nonvolatile components and color difference were measured in order toevaluate solid content and yellowing resistance in the clear coatingcomposition obtained.

<Nonvolatile Components in a Coating (NV)>

Viscosity of a coating was adjusted to 30 seconds at 20° C. by Ford CupNo. 4 using a solvent, and 0.5 g of a coating composition was preciselyweighed and, it was diluted by 3 cc of toluene, and then, baked at 110°C. for 1 hour to measure nonvolatile components (% by weight) in thecoating.

<Color Difference>

A clear coating alone was coated on two pieces of a white plate so thatlayer thickness after drying becomes 50, and one piece was baked at 160°C. for 30 minutes, and another one was baked at 140° C. for 30 minutes.Using an SM color computer SM-4 manufactured by Suga Shikenki Co., “b”value was measured in a clear layer thickness of 50 μm, and differencefrom the white plate, that is, b of 160° C. and b of 140° C. weremeasured, and the difference, (Δb)=(Δb160° C.-Δb140° C.) is defined asthe color difference.

On the other hand, a cationic electro-deposition coating (Power Top U-50manufactured by Nihon Paint, Ltd.) and a middle-coating (Orga P-2manufactured by Nihon Paint, Ltd.) were coated on a steel plate treatedby a phosphate having thickness of 0.8 mm, so that the thickness afterdrying becomes 25 μm and 40 μm, respectively, to obtain a coated testplate. And, a solvent-type high solid base coating (manufactured byNihon Paint, Ltd.) was coated by air spraying on a coated test plate sothat thickness becomes approximately 16 μm by setting for approximately7 minutes to form a base coat layer.

On the plate, the clear coating composition obtained was coated by anelectrostatic coating machine (“Auto-Rea” manufactured by Lansberg Gema,Co.) at an atomizing pressure of 5 kg/(cm)² and set for approximately 7minutes and baked at 140° C. for 25 minutes, so that the thickness afterdrying becomes approximately 40 μm.

It is to be noted that in the solvent-type high solid base coating,there are formulated 20 parts of an acrylic resin (nonvolatilecomponents of 80%, a hydroxyl group value of 100 mgKOH/g solid, an acidvalue of 30 mgKOH/g solid, and a number average molecular weight of1800) manufactured by Nihon Paint, Ltd., 30 parts of a polyester(nonvolatile components of 80%, a hydroxyl group value of 100 mgKOH/gsolid, an acid value of 12 mgKOH/g solid, and a number average molecularweight of 2600) manufactured by Nihon Paint, Ltd., 40 parts of amelamine resin “Cymel 202” (nonvolatile components of 80%) manufacturedby Mitsui Cyanamid, Co., 10 parts of a melamine resin “Cymel 327”(nonvolatile components of 90%) manufactured by Mitsui Cyanamid, Co., 10parts of “Alupaste A160-600” (nonvolatile components of 65%)manufactured by Toyo Aluminum, Co., and 7 parts of isopropylalcohol.

<Pencil Hardness>

It was conducted according to JIS K5400 8, 4.2.

<Water Resistance>

Cured coating layer obtained was immersed in a tap water at 40° C. for10 days, and coating surface was visually observed according to rulesdescribed below.

In the case that a change is not observed, it is ◯, in the case thatmarks are slightly observed, it is Δ, and in the case that a coatinglayer is abnormal, it is x.

<Abrasion Resistance>

A flannel-made cloth having 2 (cm)×2 (cm) was fitted at an abrasion headof a Gakushin type dye abrasion resistance tester (manufactured by DaieiKagaku Seiki, Co.). On the cloth, there was coated 1 g of a waterdispersion containing 50% of a cleanser (“New Homing Cleanser”manufactured by Kao, Co. (abrasive particles of 87%, a surface activeagent of 5%, and other components)). 500 g of weight was loaded to theabrasion head, and it was allowed to go and return 20 times over a curedcoating layer, followed by measuring 20-gloss in a test portion tocalculate a gloss retention ratio (%).

<Acid Resistance>

Cured coating layer obtained was immersed in 0.5 ml of 1 wt % sulphuricacid at 75° C. for 30 minutes, and coating surface was visually observedaccording to rules described below.

In the case that an abnormality is not observed, it is 5, in the casethat marks are in distinctly observed, it is 4, in the case that marksare clearly observed, it is 3, in the case that several pieces of groupsof microscopic holes are observed, it is 2, and in the case that thegroups of microscopic holes are observed as a whole, it is 1.

<Weatherability>

100 mW/(cm)² of an ultraviolet ray was irradiated in “Aisuper UV testerSUV-W13” manufactured by Iwasaki Denki, Co. for 24 hours underconditions of a black panel temperature of 63° C. and humidity of 70%,and 5 cycles were repeated as 24 hours/1 cycle which is a placing timeunder conditions of a black panel temperature of 50° C. and humidity of100%, and after that, a coating surface was visually observed accordingto rules described below.

In the case that an abnormality is not observed, it is ◯, in the casethat cracks are slightly observed, it is Δ, and in the case that cracksare remarkably observed, it is x.

<Adhesion (a Non Sand-Recoatability)>

High solid base coating (manufactured by Nihon Paint, Co.) wasair-sprayed on a coated plate on which an intermediate coating iscoated, so that thickness of a coating layer after drying becomesapproximately 16 m, followed by setting for approximately 7 minutes,provided that in the case of employing a water-based coating(manufactured by Nihon Paint, Co.), setting was conducted forapproximately 1 minute after air-spraying, followed by preheating at 80°C. for 5 minutes.

Subsequently, respective resin components were formulated in formulation(solid components) shown in Tables IX-6 and IX-7, and viscosity wasadjusted to 30 seconds by Ford Cup No. 4, and a clear coatingcomposition obtained was coated at an atomizing pressure of 5 kg/(cm)²using an electrostatic coating machine “Auto-Rea” (manufactured byLansburg Gema, Co.), so that thickness of a coating layer after dryingbecomes approximately 40 μm, followed by setting for approximately 7minutes and baking at 160° C. for 30 minutes.

A coated plate obtained was placed in a desiccator for 30 minutes and,after that, the above-described high solid base coating (manufactured byNihon Paint, Co.) was likewise coated and set again on the coated plate.The above-described clear coating composition was likewise coated andset as described hereinabove on a coating layer obtained, followed bybaking at 120° C. for 30 minutes.

On surface of a coating layer formed, cross-cuts attaining to the coatedplate passing through the coating layer were lengthwise and laterallyformed using a cutter knife (NT cutter S type or A type) at interval of2 mm, and which has lengthwise 11 lines and laterally 11 lines, whereby,100 pieces of squares were formed on the coating layer. A cellophanesticking (manufactured by Nichiban, Co.) tape having width of 24 mm wasstuck and uniformly pressed down on the coating layer having cross-cutswhile preventing formation of air bubbles by fingers. Immediately afterthat, one side of the sticking tape was abruptly pulled up vertically tostrip the sticking tape from surface of the coating layer.

Adhesion of the coating layer was evaluated according to rules describedbelow based on an area ratio in the coating layer stripped together withthe sticking tape.

<Evaluation by Area Ratio Stripped>

It is 5 in 0%, it is 4 in the case that it is less than 5% and completestrip of the squares is absent, it is 3 in the case that it is less than15% and complete strip of the square is absent, it is 2 in less than35%, and it is 1 in not less than 35%.

As a result, it was confirmed that it is able to obtain a coating layerwhich is excellent in abrasion resistance and the coating layer can becured at a low temperature and, in which other properties aremaintained.

Example X Example X-1

A four-necked flask equipped with a tube for introducing air, athermometer, a reflux condenser, and an agitating device was chargedwith 1616 parts (18.8 mol) of methacrylic acid, 1610 parts (14.1 mol) ofε-caprolactone (ε-CL), 1.99 part of hydroquinone monomethylether (HOME)which is a polymerization inhibitor, and 0.199 part of stannous chloride(SnCl₂) which is a reaction catalyst, followed by allowing to react at100° C. for 23 hours while streaming air. Reaction ratio ofε-caprolactone was 99.3%, and color hue of a reaction product was 20(APHA).

Other monomers were copolymerized with a lactone-modified methacrylatecomposition obtained to prepare an excellent acrylic polyol resin.

Example X-2

The same procedures were likewise followed as in the Example X-1, exceptthat 0.795 part of monobutyltin tris-2-ethylhexanate was employed as areaction catalyst. Reaction ratio of ε-caprolactone was 99.5%, and colorhue of a reaction product was 20 (APHA).

Other monomers were copolymerized with a lactone-modified methacrylatecomposition obtained to prepare an excellent acrylic polyol resin.

Comparative Example X-1

The same procedures were likewise followed as in the Example 1, exceptthat 0.147 part of tetrabutyl titanate (TBT) was employed as a reactioncatalyst, followed by allowing to react at 100° C. for 64 hours whilestreaming air. Reaction ratio of ε-caprolactone was 99.6%, and color hueof a reaction product was 50 (APHA).

Comparative Example X-2

A four-necked flask equipped with a tube for introducing air, athermometer, a reflux condenser, and an agitating device was chargedwith 1616 parts (18.8 mol) of methacrylic acid, 4286 parts (37.6 mol) ofε-caprolactone (ε-CL), 1.99 part of hydroquinone monomethylether (HQME)which is a polymerization inhibitor, and 0.4 part of 1 H₂O salt ofp-toluene sulphonic acid which is a reaction catalyst, followed byallowing to react at 100° C. for 16 hours while streaming air. Reactionratio of ε-caprolactone was 99.4%, and color hue of a reaction productwas 40 (APHA).

Example X-3

A four-necked flask equipped with a thermometer, a reflux condenser, atube for introducing nitrogen gas, and an agitating device was chargedwith 50 parts of butylacetate, 50 parts of toluene, and 1.0 part ofditertiary butylperoxide (DTBPO), followed by elevating a temperature to115° C. At a period having attained to 115° C., there were addeddropwise over 3 hours 17.3 parts of styrene, 17.3 parts of butylmethacrylate, 17.3 parts of butyl acrylate, 2.0 parts of methacrylicacid, 46 parts of the caprolactone-modified methacrylate compositionsynthesized in the Example 1, 0 part of methacrylic acid, and 1.0 partof azobisisobutyronitrile, and a reaction was further continued for 4hours to obtain an excellent transparent acrylic polyol resin solution.

Example X-4 and Comparative Examples X-3 and X-4

The caprolactone-modified methacrylate compositions obtained in theExample X-2 and Comparative Examples X-1 and X-2 and2-hydroxyethylmethacrlyate (HEMA) were polymerized, respectively, in thesame apparatus and formulation conditions as in the Example X-3. As aresult, although it was able to obtain an excellent transparent acrylicpolyol resin solution from the monomer obtained in the Example X-2, inthe case of the monomer obtained in the Comparative Example X-1,discoloration of a reaction liquid was remarkable during thepolymerization.

In the case of preparing a material for a coating employing the monomerobtained in the Comparative Example 2, abrasion resistance is worse in acoating layer.

It is confirmed that in the above Examples 3-4 and Comparative Example 4in which a hydroxyl value (OHV) is adjusted to 120 and Tg is adjusted to0-10° C. in the polymerization of the acrylic polyol resin, and that inExamples 3-4, a proportion of an adduct (n=1) in which one mol ofε-caprolactone is added is high, and a proportion of an adduct in whichtwo or more continuous chains of ε-caprolactone are added is low whichlowers hardness in a cured acrylic resin.

In the case of employing the adducts in which proportion of two or morecontinuous chains of ε-caprolactone are added is small as, for example,a coating material for a cars top coating, there can be obtained acoating layer well-balanced among hardness of a coating layer, afinishing appearance, weatherability, acid resistance, stainingresistance, gloss, flexibility, and abrasion resistance.

Example X-5

A glass-made flask equipped with an agitator, a reflux condenser, adropping funnel, and a thermometer was charged with 144 parts (2 mol) ofacrylic acid, 8 parts of 1 H₂O salt of p-toluene sulphonic acid, and0.08 part of hydroquinone monomethylether which is a polymerizationinhibitor, and 171 parts (1.5 mol) of ε-caprolactone was dropped over 4hours from the dropping funnel while maintaining a liquid temperature at80° C., followed by allowing to react.

After the completion of dropwise addition, a reaction was furthercontinued for 2 hours at the same temperature to terminate the reaction.As a result of a gaschromatgraphic analysis of the reaction liquid,conversion of ε-caprolactone was 99.3%.

In order to confirm a structure of a caprolactone-modified acrylatecomposition obtained, p-toluene sulphonic acid in a reaction liquid wasneutralized by a methanol solution containing 1.1 times equivalent of5%-sodium hydroxide, and an excessive amount of acrylic acid was removedat 110° C. and a reduced pressure using a rotary evaporator.

The caprolactone-modified acrylate composition was obtained by filteringa reaction liquid obtained.

Physical properties of the caprolactone-modified acrylate composition(FA075A) obtained were measured. Analytical results obtained are shownas follows.

Acid value: 3.59 mg-KOH/g

Double bond: 3.68 mg equivalent/g

Number average molecular weight converted to a polystyrene by GPC: 273

Elementary analysis: C 59.9%, H 7.6%

Further, a rational formula is as follows in the caprolactone-modifiedacrylate composition obtained, and n is 1.76.

CH₂═CH—COO(—CH₂CH₂CH₂CH₂CH₂COO—)_(n)H

Example X-6

The same procedures were followed as in the Example X-5, except that 8parts of 98% sulphuric acid was employed as an acidic catalyst toprepare a caprolactone-modified acrylate composition.

As a result of a gaschromatgraphic analysis of a reaction liquid,conversion of ε-caprolactone was 99.1%.

Further, the same operations were followed as in the Example X-5, and acaprolactone-modified acrylate composition was obtained by removingacrylic acid and filtering after neutralization of sulphuric acid.

The caprolactone-modified acrylate composition (FA075A2) obtained wasanalyzed. Results obtained are shown as follows.

Acid value: 3.61 mg-KOH/g

Double bond: 3.73 mg equivalent/g

Number average molecular weight converted to a polystyrene by GPC: 275

Example 7

The same procedures were followed as in the Example 5, except that 172parts (2.0 mol) of methacrylic acid was employed as a radicallypolymerizable unsaturated monomer having carboxylic group to prepare acaprolactone-modified acrylate composition.

As a result of a gaschromatgraphic analysis of the reaction liquidobtained, conversion of ε-caprolactone was 99.2%.

Further, the same purification were conducted as in the Example X-5, anda caprolactone-modified acrylate composition (FM075A) was obtained.

The same analysis was conducted as in the Example X-5 in relation to thecaprolactone-modified acrylate composition obtained. Results are asfollows.

Acid value: 3.41 mg-KOH/g

Double bond: 3.51 mg equivalent/g

Number average molecular weight converted to a polystyrene by GPC: 287

Comparative Example X-5

The same procedures were followed as in the Example X-5, except that 236parts (2 mol) of ε-caprolactone was employed to prepare acaprolactone-modified acrylate composition.

The caprolactone-modified acrylate composition (FA200A) was obtained byfiltration of a reaction liquid obtained.

Physical properties were measured in relation to thecaprolactone-modified acrylate composition obtained. Analytical resultsobtained are as follows.

Acid value: 3.30 mg-KOH/g

Double bond: 3.38 mg equivalent/g

Number average molecular weight converted to a polystyrene: 297

Elementary analysis: C 59.9%, H 7.6%

Further, “n” is 1.97 in the caprolactone-modified acrylate compositionobtained.

Likewise, acrylic acid was allowed to react with ε-caprolactone in molarratio of 1/0.5 to obtain FA050A for Example.

Likewise, methacrylic acid was allowed to react with ε-caprolactone inmolar ratio of 1/0.5 to obtain FM050A for Example, and methacrylic acidwas allowed to react with ε-caprolactone in molar ratio of 1/2.0 toobtain FM200A for Comparative Example.

Results are shown in Table X-1.

lactone-added average-added numbers 0 1 2 3 4 Total numbers Mn beforeremoval of AA FA050A 35.1 39.5 19 5.2 1.1 99.9 0.98 183 after removal ofAA 0.0 61.0 29.3 8.0 1.7 100.0 1.50 244 before removal of AA FA075A 23.436.4 25.8 10.5 3.9 100.0 1.35 226 after removal of AA 0 47.5 33.7 13.75.1 100.0 1.76 273 before removal of AA FA200A 16.3 32.2 28.9 14.8 7.699.8 1.65 260 after removal of AA 0 38.6 34.6 17.7 9.1 100.0 1.97 297before removal of MAA FM050A 38.2 38.3 17.7 4.8 1 100.0 0.92 191 afterremoval of MAA 0 62.0 28.6 7.8 1.6 100.0 1.49 256 before removal of MAAFM075A 23.4 36.4 25.8 10.5 3.9 100.0 1.35 240 after removal of MAA 047.5 33.7 13.7 5.1 100.0 1.76 287 before removal of MAA FM200A 16.3 32.228.9 14.8 7.6 99.8 1.65 274 after removal of MAA 0 38.6 34.6 17.7 9.1100.0 1.97 311

Application Example

A four-necked flask equipped with a thermometer, a reflux condenser, atube for introducing nitrogen gas, and an agitator was charged with 50parts of butyl acetate, 50 parts of toluene, and 1.0 part ofditertiarybutyl peroxide (DTBPO), followed by elevating a temperature to115° C. At a period having attained to 115° C., there were addeddropwise over 3 hours 17.3 parts of styrene, 17.3 parts of butylmethacrylate, 17.3 parts of butyl acrylate, 2.0 parts of methacrylicacid, 46 parts of the caprolactone-modified methacrylate compositionsynthesized in the Example 5, 0 part of 2-hydroxyethylmethacrylate, and1.0 part of azobisisobutyronitrile, and a reaction was further continuedfor 4 hours to obtain an excellent transparent acrylic polyol resinsolution.

In the case of employing a coating having a low proportion of theadducts in which not less than 2 mol of ε-caprolactone is added as, forexample, a top-coating material for cars, there can be obtained acoating layer which is well-balanced among a hardness of a coatinglayer, a finishing outer appearance, weatherability, acid resistance,stain resistance, gloss, flexibility, and abrasion resistance.

Possibility of Utilization in Industry

According to the present inventions No. I to No. VII, there can beobtained a hydroxyalkyl(meth)acrylate composition modified by a smallamount of lactones, an acrylic polyol resin (A) obtained by allowing toreact the composition with other ethylenic unsaturated monomer, and acurable resin composition containing the resin can be employed as a rawmaterial for, for example, a well-balanced high quality finishing agentfor industry, for example, a coating, a pressure sensitive adhesive, anultraviolet ray- and electron beam-curable coating agent, and a reactiveimprover, etc. by formulating various conventional crosslinking agentsand usually employed components.

A composition containing the curable resin composition is excellent inworkability, water resistance of a coating layer, acid rain resistance,staining resistance, retort resistance, adhesion, a low temperaturecurability, and wet ink adaptability and, by which there can be prepareda coating well-balanced between abrasion resistance and acid resistance,which is excellent in flexural resistance and recoat adhesion, and whichcan be employed as a raw material for coatings for cars, home electricappliances, a water-based coating for coating an outside and inside ofcans for foods and beverages, particularly, a clear coating forfinishing an outside of the cans, and a top coating for cars.

In a conventional type coating composition using a layer-formable resin,even in the case of employing a melamine resin curing agent causing aworse acid resistance, there is produced a large merit that any problemsare not caused by the use of a coating of the present invention.

The carboxylic group-contained acrylate monomer composition modified bya small amount of lactones in the present inventions No. VII to No. VIIIhas (meth)acryloyl group and carboxylic group in the molecule, and ithas an effect in adhesion to a metal and other materials, solubility towater and an aqueous alkali solution and, above-all, reduction of adeveloping time of period in an alkali developing step for forming apattern utilizing ultraviolet ray curing, and an improvement in removalproperty of an uncured portion. Further, the compound of the presentinvention can be industrially prepared at economical cost by anapplicable method for the preparation thereof.

From the curable resin composition prepared by polymerization of thecarboxylic group-contained acrylate monomer composition modified by asmall amount of lactones, a high solid coating can be prepared, and acoating layer obtained from the coating is excellent in acid resistanceagainst acidic rain, abrasion resistance, yellowing resistance, andouter appearance, and the coating can be cured at low temperature.

The polyester unsaturated monomer modified by a small amount of lactonesof the present invention No. X can be readily prepared by an industrialfashion in a short step.

Since the polyester unsaturated monomer modified by a small amount oflactones obtained has one radically polymerizable unsaturated group, andit has carboxylic group at terminal, there can be widely expected anapplication as a raw material or an intermediate for a thermosettingcoating, an adhesive, a crosslinking agent, a stabilizer for anemulsion, a dispersant, and an emulsifier, etc.

Further, in a composition using the polyester unsaturated monomermodified by a small amount of lactones, since tackiness can be removedby elevating Tg of the composition, it is particularly useful in anelectric material field, etc.

Still further, there can be obtained the polyester unsaturated monomermodified by a small amount of lactones in which discoloration is low.

According to the present invention, there can be prepared a polyesterunsaturated monomer modified by a small amount of lactones in which theamount of the lactones added is not less than 0.3 and more than 1 mol,and which has an identical radical polymerizable functional group to thenumber of a radical polymerizable functional group existing in aradically polymerizable unsaturated monomer having carboxylic groupwhich is employed as a raw material. Particularly, in the case thatacrylic acid and methacrylic acid are employed as the radicallypolymerizable unsaturated monomer having carboxylic group, there can beproduced a polyester unsaturated monomer modified by a small amount oflactones which certainly has one piece of a radically polymerizablefunctional group without producing a compound not containing theradically polymerizable functional groups at all and a compound havingtwo or more pieces of the radically polymerizable functional groups.

The polyester unsaturated monomer modified by a small amount of lactonesobtained is characterized in that it has reactive carboxylic group atone terminal and, further, it has a radically polymerizable unsaturatedgroup apart from the carboxylic group.

What is claimed is:
 1. A curable resin composition comprising: (i)0.5-80 parts by weight of an acrylic polyol resin (A) comprising ahydroxyalkyl(meth)acrylate composition having 0.3 to less than 1.0 moleof polymerized lactone monomer being polymerized by ring-opening withrespect to 1 mole of hydroxyalkyl(meth)acrylate, wherein the content ofthe lactone monomer in the hydroxyalkyl(meth)acrylate composition is0-10% by weight, and a proportion of monomers having two or morecontinuous chains (n≧2) of lactones less than 37.4% (area by GPC), thehydroxyalkyl(meth)acrylate composition being represented by formula (1)described below,

where R, R¹, R², and R³ are independently a hydrogen or a methyl group,“j” is an integer of 2-6, xn pieces of R⁴ and R⁵ are independently ahydrogen or an alkyl group having a carbon number of 1-12, “n” is aninteger greater than or equal to zero, and an average value of “n” inthe composition is not less than 0.3 to less than 1.0, and (ii) 0.5parts by weight of a melamine resin (B), wherein the total of (A) and(B) does not exceed 100 parts by weight.
 2. A curable resin compositionas claimed in claim 1, wherein said hydroxyalkyl(meth)acrylatecomposition is obtained using a hydroxyethyl (meth) acrylate.
 3. Athermosetting resin composition which comprises: 2-50 parts of anacrylic polyol resin (VII-A) containing a the hydroxyalkyl(meth)acrylatecomposition comprising 0.3 to less than 1.0 mole of polymerized lactonemonomer being polymerized by ring-opening with respect to 1 mole ofhydroxyalkyl(meth)acrylate, wherein the content of the lactone monomerin the hydroxyalkyl(meth)acrylate composition is 0-10% by weight, and aproportion of monomers having two or more Continuous chains (n≧2) oflactones less than 37.4% (area by GPC), the hydroxyalkyl(meth)acrylatecomposition being represented by formula (1) described below,

where R, R¹, R², and R³ are independently a hydrogen or a methyl group,“j” is an integer of 2-6, xn pieces of R⁴ and R⁵ are independently ahydrogen or an alkyl group having a carbon number of 1-12, “x” is 4-7,“n” is an integer greater than or equal to zero, and an average value of“n” in the hydroxyalkyl(meth)acrylate composition is not less than 0.3to less than 1.0, and 30-80 parts of an acrylic copolymer (VII-B) havingan alkoxylsilyl group, wherein the total of (VII-A) and (VII-B) is 100parts by weight.
 4. A thermosetting resin composition as claimed inclaim 3, wherein said acrylic polyol resin (VII-A) has at least one kindof group selected from the group consisting of an acid anhydride group,an epoxy group, amino group, and carboxylic group.
 5. A method for thepreparation of a carboxylic group-containing acrylate composition (a′)represented by a general formula (VIII-3) described below, said methodcomprising: reacting a hydroxyalkyl(meth)acrylate composition, saidhydroxyalkyl(meth)acrylate composition comprising 0.3 to less than 1.0mole of polymerized lactone monomer being polymerized by ring-openingwith respect to 1 mole of hydroxyalkyl(meth)acrylate, wherein thecontent of the lactone monomer in the composition is 0-10% by weight,and a proportion of monomers having two or more continuous chains (n≧2)of lactones less than 37.4% (area by GPC), the composition beingrepresented by formula (1) described below,

where R, R¹, R², and R³ are independently a hydrogen or a methyl group,“j” is an integer of 2-6, xn nieces of R⁴ and R⁵ are independently ahydrogen or an alkyl group having a carbon number of 1-12, x is 4-7, “n”is an integer greater than or equal to zero, and an average value of “n”in the composition is not less than 0.3 to less than 1.0, with acarboxylic acid or anhydride thereof (VIII-b) represented by a generalformula (VIII-2) described below,

(in the formula, R, R¹, R², and R³ are independently a hydrogen or amethyl group, j is an integer of 2-6, xn pieces of R⁴ and R⁵ areindependently a hydrogen or an alkyl group having a carbon number of1-12, “x” is 4-7, “n” is an integer greater than or equal to zero, anaverage value of “n” in said composition is not less than 0.3 to lessthan 1.0, R⁹ is a residual group of a carboxylic acid, and “m” is aninteger of 1-3).
 6. A method for the preparation of a carboxylicgroup-contained acrylate composition (a′) as claimed in claim 5, whereinsaid reaction of said hydroxyalkyl(meth)acrylate composition with saidcarboxylic acid or anhydride thereof (VIII-b) is conducted at atemperature range of 40-160° C.
 7. A curable resin composition whichcomprises 10-70 parts of an acrylic polycarboxylic acid resin (A′)comprising: the carboxylic group-containing acrylate composition (a′),comprising a small amount of lactones, represented by the generalformula (VIII-3) as claimed in claim 5, in which a proportion ofmonomers having not less than 2 continuous chains (n≧2) of lactones isless than 50% (GPC area %), as a polymerizing component, and 10-80 partsof a polyepoxide (IX-B).
 8. A curable resin composition as claimed inclaim 7, wherein said carboxylic group-containing hydroxy(meth)acrylatecomposition (a′) is obtained by allowing to react saidhydroxyalkyl(meth)acrylate composition, in which a proportion ofmonomers having not less than 2 continuous chains (n≧2) of lactones isless than 50% (GPC area %), with said carboxylic acid or anhydridethereof represented by the following general formula: R⁹—[COOH]_(m+1)wherein R⁹ is a residual group of a carboxylic acid, and “in” is aninteger of 1-3.
 9. A curable resin composition as claimed in claim 8,wherein said carboxylic group-containing hydroxy(meth)acrylatecomposition (a′) comprising a small amount of lactones is obtained byallowing to react 0.9-1.1 mol of said carboxylic acid or anhydridethereof with respect to 1 mol of said hydroxy(meth)acrylate composition(a) comprising a small amount of lactones.
 10. A method for thepreparation of a polyester unsaturated monomer composition, comprising asmall amount of lactones, wherein 0.3-less than 1.0 mole of a lactonemonomer is polymerized by ring-opening with respect to 1 mole of aradically polymerizable unsaturated monomer containing carboxylic group,whereby, a proportion of monomers having not less than 2 continuouschains (n≧2) of lactones is adjusted to less than 50% (GPC area).
 11. Amethod for the preparation of a polyester unsaturated monomercomposition comprising a small amount of lactone as claimed in claim 10,wherein an acidic catalyst is a Lewis acid or a Bronsted acid.
 12. Amethod for the preparation of a polyester unsaturated monomercomposition comprising: polymerizing, by ring-opening, 0.3 - less than1.0 mole of a lactone monomer with respect to 1 mole of a radicallypolymerizable unsaturated monomer containing carboxylic group by usingstannous halide, monobutylin tris-2-ethylhexanate, stannous octoate,dibutylin dilaurate, or a mixture thereof as a catalyst, and separatingthe unreacted radically polymerizable unsaturated monomer containingcarboxylic group.
 13. A method of the preparation of a polyesterunsaturated monomer composition as claimed in claim 12, wherein thecatalyst to be employed in said polymerization is less than 1000 ppm byweight based on total amount to be fed.